Before you begin your draft, gather all the information you will need to include in your complaint. This information may include the time, date, and location that you purchased faulty goods or services, reference or invoice numbers, and records of previous communication with the company. To support your complaint, you may need to enclose copies of documents such as receipts with your letter.

How to structure your letter of complaint:

Your letter of complaint should follow the standard composition format for a formal letter. See how to lay out a letter.

Below the recipient’s address, include a subject line to indicate the product or service that you are addressing in your complaint. In the first body paragraph, open with a sentence that immediately draws the reader's attention to the matter, e.g.:

Follow the opening sentence with a summary of the events that prompted your complaint. Be sure to include exact dates and times, and give all the relevant information in a clear and logical sequence.

In the next paragraphs, you should outline what steps you have taken thus far to resolve the matter and describe the consequences of the faulty product or service. Adding specific details, such as additional costs you have incurred to replace a faulty product, will strengthen your complaint. If you have had previous communication with the company, be sure to note it in your letter; include reference numbers where applicable.

In the final body paragraph of your letter, you should state your expectations of how the company should resolve the matter, including specific actions and deadlines, e.g.:
I would appreciate it if you could replace the missing part by next week.

I look forward to hearing from you within the next ten days.