Hello, this is a formal letter where I am a buyer at a mail order company, and I've decided to reduce the size of next year's catalogue.

Dear Mr. Xxx,

I am writing regarding the annually order for the catalogue of my business.

Ensemble my associates, we have finalised our report of buying policies and we have decided to reduce the size of next year's collection.
As a result, we would like to buy the following items:

Item Article no Quantity
Scanner Sony A 1122 200
Printer Asus A 1456 200
Printer Asus B 1457 100

This, of course, means cancelling other types of scanners and printers this year.

We are sorry for any inconvenience this has caused, but we have to fit at the new technology market's conditions.
We confirm the 1st November as the date for delivery.

We hope this will not have any consequence on our collaboration and that we will continue it in the future.

We look forward to hearing from you soon.

Is it ok to use "catalogue" and "collection" like synonyms in this context?

I don't agree with the book that says to apologise for the cancellation first, then confirm the date for the order and then mention work together in the future; it is not better do the second thing and then apologise and mention work together?