•Include your name, address, and home and work phone numbers.
•Type your letter if possible. If it is handwritten, make sure it is neat and easy to read.
•Make your letter brief and to the point. Include all important facts about your purchase, including the date and place where you made the purchase and any information you can give about the product or service such as serial or model numbers or specific type of service.
•State exactly what you want done about the problem and how long you are willing to wait to get it resolved. Be reasonable.
•Include all documents regarding your problem. Be sure to send COPIES, not originals.
•Avoid writing an angry, sarcastic, or threatening letter. The person reading your letter probably was not responsible for your problem but may be very helpful in resolving it.
•Keep a copy of the letter for your records.
Read more: How to Write a Complaint Letter http://www.infoplease.com/ipa/A0002121.html#ixzz3YUMnPWmu