How to Write a Formal Complaint Letter: Format, Example & Template

A formal complaint letter should be polite but direct. State the problem clearly in your opening paragraph, provide the factual background in the middle paragraph, and set out exactly what you want the company to do in your final paragraph. Keep a firm but respectful tone throughout - avoid emotional language.

Whether you are a consumer writing to a company about a faulty product, or an IELTS General Training candidate preparing for Task 1, a complaint letter follows a reliable structure that makes your grievance clear and your desired outcome impossible to ignore. This guide covers the correct format, a full annotated example, a template you can adapt, and specific tips for IELTS candidates.

What Makes a Good Complaint Letter?

A complaint letter is a formal written communication sent to a company, organisation, or individual to report a problem and request a specific remedy. It is distinct from an informal complaint in that it creates a written record, follows a fixed format, and typically carries greater legal weight.

The most effective complaint letters share five qualities:

• Factual. State dates, amounts, order numbers, and specific events. Avoid vague claims such as "your service is always bad."
• Specific. Describe exactly what went wrong. A reader who was not present should be able to understand the situation fully from your letter alone.
• Polite. A professional tone is not just courteous - it is more effective. Aggressive or threatening letters are easier to dismiss and may undermine your legal position.
• Action-oriented. Make your desired outcome explicit. Do you want a refund, a replacement, a repair, or an apology? Say so.
• Concise. One page is the target. Include what is necessary; leave out what is not.

Complaint Letter Format

A complaint letter follows standard formal letter format. The steps below reflect UK convention (fully blocked layout, all text aligned to the left margin).

1. Your address and contact details
   Write your full postal address, telephone number, and email address at the top right of the page. This tells the company how to reach you and establishes you as an identifiable customer.
2. Company address
   Below and to the left, write the recipient's name and job title (if known), the company name, and the company's postal address. Addressing it to a specific person - such as the Customer Services Manager - increases the chance it reaches the right desk.
3. Date
   Write the date in full (e.g. 12 April 2026). Leave a line space above and below the date.
4. Reference line: Re:
   Add a line beginning Re: (short for the Latin res, meaning "matter" or "thing") followed by your order number, account reference, or a brief subject description - for example, Re: Order No. HE-88423 - Faulty Appliance. This is not mandatory in a personal letter, but it is standard in business and consumer correspondence. It allows the company to locate your records before reading a single sentence of the body.
5. Salutation
   Use Dear Mr / Ms [Surname] if you know the name of the person you are writing to, or Dear Sir or Madam if you do not. For guidance on when to use each, see our formal letter writing guide.
6. Three-paragraph body
   Paragraph 1 states the problem. Paragraph 2 provides the factual background and evidence. Paragraph 3 states the outcome you require. Each paragraph should do one job and do it clearly.
7. Sign-off
   Use Yours sincerely if you addressed the letter to a named person, or Yours faithfully if you used Dear Sir or Madam. Sign above your printed full name. If you have a reference number from previous correspondence with the company, you can add it below your name.

Complaint Letter Structure - Paragraph by Paragraph

Paragraph 1: State the Problem

Your opening paragraph should identify who you are, what you purchased or used, and what went wrong - all in two or three sentences. Do not bury the complaint in background detail. The reader needs to understand immediately that this is a letter of complaint and what it concerns.

I am writing to complain about a washing machine (Model No. WM-400X) that I purchased from your store on 3 March 2026. The appliance developed a significant fault within ten days of installation and has been unusable since 14 March 2026.

Paragraph 2: Provide the Background and Evidence

The middle paragraph gives the facts in chronological order: what happened, when, and what steps you have already taken. If you have spoken to customer services, quote any reference numbers given. If you have documentary evidence - a receipt, an email, a photograph - mention it here and attach copies (never originals).

I contacted your customer services team by telephone on 15 March and was allocated the reference number CS-2026-7741. I was advised that an engineer would visit within five working days. As of the date of this letter, no appointment has been arranged and my most recent call on 28 March was not returned. I have enclosed a copy of my original receipt and the email confirmation of my telephone complaint.

Paragraph 3: State Your Desired Outcome

This is the most important paragraph in practical terms. Tell the company specifically what you want them to do - and, where appropriate, give a deadline. A letter that ends with "I hope you will look into this" is easy to set aside. A letter that ends with a clear demand and a reasonable deadline is not.

I would ask that you arrange a repair or full replacement of the appliance within fourteen days of the date of this letter. If this is not possible, I require a full refund of the purchase price of £549.00. I look forward to your response.

Full Complaint Letter Example

The letter below is a complete, realistic example of a formal complaint letter from a customer to a retailer about a faulty product. Each section is labelled for reference.

[Your address - top right]
Sarah Thornton
14 Kestrel Avenue
Bristol
BS6 7RQ
Tel: 07700 912 384
Email: s.thornton@mailexample.co.uk

[Company address - left]
The Customer Services Manager
Hartfield Electronics Ltd
Unit 7, Pendleton Retail Park
Bristol
BS1 4NP

[Date]
1 April 2026

[Reference line]
Re: Order No. HE-88423 - Faulty Washing Machine (Model WM-400X)

[Salutation]
Dear Sir or Madam,

[Paragraph 1 - State the problem]
I am writing to complain about a washing machine that I purchased from your Pendleton Retail Park branch on 3 March 2026. The appliance (Model WM-400X, serial number 4471-BC-28) developed a significant electrical fault within ten days of installation. Since 14 March 2026, the machine has failed to complete any wash cycle and displays a persistent error code (E7) that your user manual states requires professional attention.

[Paragraph 2 - Background and evidence]
I reported the fault to your customer services team by telephone on 15 March and was allocated the reference number CS-2026-7741. I was advised that an engineer would attend within five working days. As of the date of this letter, no appointment has been made. I followed up by telephone on 22 March and again on 28 March; on the latter occasion I was placed on hold for twenty minutes and the call was not answered. I have enclosed copies of my original receipt, the manufacturer's guarantee, and a photograph of the error display. The machine is still within its twelve-month manufacturer's guarantee period.

[Paragraph 3 - Desired outcome]
I would ask that Hartfield Electronics arrange a repair or a like-for-like replacement of the appliance within fourteen days of the date of this letter. If neither is possible, I require a full refund of the purchase price of £549.00 under the Consumer Rights Act 2015. I would be grateful if you would contact me at the telephone number or email address above to confirm the action you intend to take.

[Sign-off]
Yours faithfully,

[Signature]

Sarah Thornton

Enc: Sales receipt, manufacturer's guarantee, photograph of error display

Notes on this example: The letter uses Yours faithfully because the salutation is Dear Sir or Madam (the writer does not know the name of the recipient). The Enc: line at the bottom lists documents enclosed with the letter - a useful convention for formal complaints. The Consumer Rights Act reference is not aggressive; it is informative, and it signals that the writer knows their rights.

Complaint Letter Template

Use this template as your starting point. Replace the details in italics with your own information.

Your name
Your address
Your telephone number
Your email address

Recipient's name and title (if known)
Company name
Company address

Date

Re: [Order number / account reference / subject of complaint]

Dear [Sir or Madam / Mr - Ms Surname],

I am writing to complain about [describe the product, service, or situation], which I [purchased / used / experienced] on [date]. [State what went wrong in one or two sentences.]

[Describe the factual background in chronological order. Include dates, reference numbers from previous contact, and any steps you have already taken. Mention any evidence you are enclosing.]

I would ask that you [state the specific outcome you require: refund / replacement / repair / apology] within [reasonable timeframe, e.g. fourteen days] of the date of this letter. I look forward to your response.

Yours [sincerely / faithfully],

[Signature]

Your printed name

Enc: [List any documents enclosed, or delete this line if none]

IELTS Complaint Letter Tips

Complaint letters are one of the most commonly tested formats in the IELTS General Training Writing Task 1. If you are preparing for IELTS, the following notes will help you meet examiner expectations.

Common IELTS Scenarios

IELTS complaint letter prompts typically ask candidates to write to a manager, landlord, or company about one of the following:

• A faulty product purchased from a shop
• A problem with rented accommodation
• Poor service at a hotel, restaurant, or leisure facility
• Noise, disruption, or another issue caused by a neighbour or local business
• A problem with a course, class, or educational service

What IELTS Examiners Look For

• Task Achievement: You must address all three bullet points given in the prompt. Each bullet point should correspond roughly to one paragraph of the body. Missing a bullet point will significantly reduce your Task Achievement score.
• Formal register: The complaint letter task requires a formal or semi-formal tone. Avoid contractions (don't, I've) in the body of the letter. Use formal vocabulary throughout.
• Cohesion: Use linking phrases to move between paragraphs (e.g. Furthermore, As a result, I would therefore ask that).
• Word count: Task 1 requires a minimum of 150 words. Aim for 160–180 words - enough to cover the task fully without padding.
• Opening and closing: Use a formal salutation and sign-off. In IELTS, you will often be told to write to a named person (e.g. "Write to the manager, Mr James Taylor") - in that case, use Dear Mr Taylor and close with Yours sincerely.

A Note on Register

One of the most common reasons IELTS candidates lose marks on complaint letters is inconsistent register - starting formally and then slipping into casual language mid-letter. Read your letter through once asking: "Would I be comfortable submitting this to a real company?" If the answer is yes, the register is likely appropriate.

Common Mistakes in Complaint Letters

• Being too aggressive. Phrases such as "This is absolutely disgraceful" or "I demand an immediate response or I will take legal action" may feel satisfying to write, but they put the recipient on the defensive and are less likely to produce a quick resolution. Keep the tone firm but civil.
• Being too vague. "The product was unsatisfactory" tells the company nothing useful. Include specific details: what the product is, what it did or failed to do, and when.
• Not stating what you want. The most common failure in complaint letters is an ending that expresses dissatisfaction but makes no specific request. Always close with a clear demand.
• Not keeping a copy. Always keep a copy of the letter and any enclosures. If the matter escalates to a regulator or court, your copy is your evidence.
• Sending originals rather than copies. Enclose photocopies or scanned copies of receipts, warranties, and correspondence - never the originals. You may need them later.
• Repeating the same point in multiple paragraphs. A well-structured complaint letter states each point once, clearly. Repetition makes a letter harder to read and can obscure the key facts.

Useful Phrases for a Complaint Letter

The phrases below can be adapted to suit your specific situation. They are organised by the stage of the letter at which they are most useful.

Opening the Complaint

• I am writing to complain about…
• I am writing to draw your attention to a serious problem with…
• I wish to formally complain regarding…
• I am writing in connection with an unsatisfactory experience I had at / with…

Describing the Problem

• The [product / service] failed to meet the standard I would reasonably expect because…
• Despite [number of] attempts to resolve this through your customer services team…
• I have enclosed a copy of [receipt / email / photograph] as evidence of…
• As of the date of this letter, the matter remains unresolved.

Stating Your Desired Outcome

• I would ask that you arrange a full refund / repair / replacement within [timeframe].
• I require a written explanation of…
• I would be grateful if you could confirm in writing that…
• In the absence of a satisfactory response within [timeframe], I will have no alternative but to refer this matter to [Trading Standards / the relevant ombudsman / my solicitor].

Closing the Letter

• I look forward to your response.
• I would appreciate a response within fourteen days.
• I trust this matter will be resolved promptly.
• Please do not hesitate to contact me at the above address if you require further information.

Frequently Asked Questions

Related Guides

• How to Write a Formal Letter - the complete guide
• Business Letter Format: Layout, Examples & UK/US Differences
• How to Format a Cover Letter