If sales or use tax has been erroneously paid since January 1, 2000, taxpayers will no longer be eligible for vendor credits when the overpayment is discovered on audit and the statute of limitations for seeking abatement has passed. The taxpayer should seek a refund from the vendor to whom tax was paid, if tax has been erroneously paid on an exempt item. (Directive 02-17, Massachusetts Department of Revenue, December 23, 2002)