HENNERY SMITH
2365 S Mayfield Ave
Chicago, IL 60652
Cell: (123)-555-1234
[Subject: Normally bold, summarizes the intention of the letter] -Optional-
Dear Hennery smith,
Thank you very much for letting us know about the double-billing error that was reflected in your last statement. we are very sorry to have made such a serious mistake and are thankful that you were able to spot it and call our attention immediately. We have enclosed a check to reimburse you for the extra amount that you had already paid for. Thank you very much for being patient with us.
Sincerely,
Chris payle