A complaint to the store manager

[greenhouse]

Please help me how to write this letter properly. THANKS

To: Manager of the superstore

This evening, while I was helping myself to get a bag of bread from the stack in your store, I have noticed that one of the bread bags had yellowish, thick liquid spread on it. As a regular customer in your store, I was very disappointed and disgusted to see such item was stored like that on the stack. I would like to bring this matter to your attention so that you look into this matter seriously and take necessary steps to maintain your stacks properly.

Thank you,

 

[teechar]

Note that I have changed the title of your thread to "A complaint to the store manager."
"Complain" is a verb.

 

[emsr2d2]

Please help me [STRIKE]how[/STRIKE] to write this letter properly. [STRIKE]THANKS[/STRIKE] Thanks.

To: The Manager [name of store] [STRIKE]of the superstore[/STRIKE]

This evening, while I was [STRIKE]helping myself to get[/STRIKE] taking a bag of bread from the stack in your store, I [STRIKE]have[/STRIKE] noticed that one of the bread bags had yellowish, thick liquid spread on it. As a regular customer in your store, I was very disappointed and disgusted to see such a thing. [STRIKE]item was stored like that on the stack.[/STRIKE] I would like to bring this matter to your attention so that you can look into this matter [STRIKE]seriously[/STRIKE] urgently and take the necessary steps to maintain your [STRIKE]stacks[/STRIKE] products properly.

Thank you.

See my changes above.

"while I was helping myself to get a bag of bread" is not natural. Usually, when we say that we "help ourselves" to something, it means that we take it when perhaps we should have got someone else to get it for us, or even that we steal it! You don't need help from anyone, including yourself, to simply take bread from a shelf in a shop.
Also, in BrE at least, we don't say "a bag of bread". It's usually a loaf of bread, even if it's wrapped in a bag made of plastic.