How do I request a refund of an overpayment? We have identified the following overpayment and are in good faith voluntarily refunding all monies collected in error.Overpayment Information. If you have received an overpayment notice from DETR, you may be required to repay the excess amount. FILLING OUT THE FORM​​ Once the party to whom the refund is due is clearly identified, they must fill out the Refund Request form. Gov or mailed to the address above. In this article, we'll show you how to write a refund request letter template that not only grabs attention but also persuades companies to act in your favor. The salary overpayment resulted because . A refund request of a valid overpayment must be received within 1 year of when the tax was due. Choose the reason(s) for the refund request and provide a brief explanation in the space provided below.