If it shall appear that an amount of tax has been paid which was not due under the provisions of this chapter, whether as the result of a mistake of fact or an error of law, then such amount shall be credited against any tax due, or to become due, under this chapter from the retailer who made the erroneous payment; provided, that no amounts erroneously paid more than three (3) years prior to the filing of a claim therefor shall be so credited; and provided further, that the retailer reasonably described such overpayment on the tax return. (Ord. 1375, 7-23-2002)