This brief but important letter notifies a customer that he or she has overpaid you. It can serve as a very good customer relations letter.Our document template is designed to make the process of writing an "Inform a Customer of an Overpayment" letter quick, easy, and stress-free. Our service provides various examples of refund letters, including sample overpayment letters, refund request letters, and more. The salary overpayment resulted because . Tell them that they have "overpaid" you. Then ask them to ring you for details. In this article, we'll provide tips on how to handle refund request letters and 7 sample templates you can use to get started today! B. Front End Detection System (FEDS). We have identified the following overpayment and are in good faith voluntarily refunding all monies collected in error.