We have identified the following overpayment and are in good faith voluntarily refunding all monies collected in error. For example, use Form 8849 to claim a refund for an overpayment of excise taxes reported on Form(s) 11C or 2290.If we have identified an overpayment and request a refund, please mail the check along with a copy of the overpayment request letter we sent you. To do this, go to your MiWAM account and click on the Claimant Services Tab. The ITR letter advises you to refund the overpayment or establish an ERS. If you don't, the MAC refers the debt for collection. It's important that you also include a completed refund form. This completed form allows us to apply the refund to the correct claim overpayment.