Sample Letter #1
Thank you for pointing out the error in the supplies invoice. It appears that a typist transposed two numbers. I am canceling that invoice and am sending you a new one with the correct amount. Don’t worry about sending payment until you receive the corrected invoice. Thank you for your patience and understanding.
Sample Letter #2
After you informed us of an error on your January bill, we investigated the matter and admit the mistake was ours. Until our new automated system is online, we are still subject to the frailties of human error. Rest assured that your account has been credited as you will see on your next bill. Thank you for your help in rectifying this matter. We apologize and look forward to serving you in the future.