The notice will provide the tax type from which the overpayment originated and tax type to which it is being applied. Complete the paper OSIG 189 Overpayment Referral form and obtain the Buy-In amounts overpaid using Data Exchange 7.When claims are adjusted due to an overpayment, a Solicited Demand letter will be issued to you. Completing the Overpayment Referral form (OIG 189):. Completion of the OIG 189 is required to refer MA overpayments to the OIG. Looking online it says that Non fraud overpayments can be paid through unemployment over the next 3 -4 years.