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. 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! The salary overpayment resulted because . Often, if you take the blame, the customer is likely going to say "it's okay, we're all human," and then get past it. We have identified the following overpayment and are in good faith voluntarily refunding all monies collected in error.