123, X Street, Y Avenue
[Subject: Normally bold, summarizes the intention of the letter] -Optional-
Dear Austin Park,
I am writing to inform you that I will no longer renew my postpaid plan with BRIGHT Telecommunications. My 2 year lock-up with your company will end on March 30th and I have already paid the applicable fees and remaining balance at your wireless center. Thank you and all the best to your company.