To write a customer complaint letter, first research the name of the person in the company who handles complaints, and address the letter specifically to that person, including his job title. In the body of the letter, include the details surrounding the complaint, including the date and time, as well as the names of any employees involved.
If applicable, include a customer account number or transaction number so the person handling the complaint can access any digital information about the incident. Remain respectful and positive when describing the situation. Avoid hostility or anger, and clearly state that you understand that mistakes happen, but you hope the company is able to correct the situation to both sides' satisfaction.
Request a reply, giving a reasonable deadline for the correction. If there is no response in the time indicated in the letter, send a follow-up letter or make a call to the corporate offices. If you receive a positive response, send a thank-you note to indicate that the issue is resolved. If no positive action is taken to resolve the issue, even after a follow-up letter, consider sending correspondence to another employee who has higher rank or reporting the issue to the local Better Business Bureau office.