When an overpayment has occurred, the provider should immediately refund the Oklahoma Health Care Authority, by check, to the attention of the Finance Division, P.O. Box 18299, Oklahoma City, OK 73154.  In refunding OHCA, be sure to clearly identify the account to which the money is to be applied.  The MMIS system has the capability of automatic credits and debits.  When an erroneous payment occurs, which results in an overpayment, an automatic recoupment will be made to the provider's account against monies owed to the provider.  For more specific information, refer to the Oklahoma Medicaid Provider Billing Manual, Chapter 9: Paid Claim Adjustment Procedures.