Our document template is designed to make the process of writing an "Inform a Customer of an Overpayment" letter quick, easy, and stress-free. This memorandum serves as notification of an overpayment of wages that you received and the subsequent repayment that is your responsibility.The salary overpayment resulted because . . . We have identified the following overpayment and are in good faith voluntarily refunding all monies collected in error. Our templates include various examples such as sample overpayment letter, overpayment letter template, and overpayment letter example. They use the following sample letter.