Dear ( fill in the blink),
I am writing to you to make a complaint about (write down the thing you are complaining about)
Enclosed is a written account of the events that transpired, and I have also included some supporting documents as well.
I wish to (put down what you want the company to do about your complaint)
I look forward to your response to this matter.
Sincerely,
[Senders Name]
[Senders Title] -Optional-
[Enclosures: number] - Optional -
cc: [Name of copy recipient] - Optional -