1.    The governing body of any incorporated city that has adopted the home rule provisions of chapter 40-05.1 or of any county which has adopted the home rule provisions of chapter 11-09.1 must enter a contract with the tax commissioner giving the tax commissioner authority to collect any sales, use, or gross receipts taxes assessed by such incorporated city or county.

2.    The tax commissioner shall deposit with the state treasurer all money collected under a contract under this section and accompany each remittance with a certificate showing the city or county for which it was collected. The state treasurer, monthly, shall pay to the auditors of cities or counties the money to which cities or counties are entitled under a contract under this section.

3.    Contracts under this section shall provide for an agreed amount to be allowed the tax commissioner for services. Any sums collected for services rendered must be paid to the state treasurer for deposit in the general fund.

4.    A person required to collect and remit sales or use taxes may not be required to register with, file returns with, or remit funds to anyone other than the tax commissioner or the tax commissioner’s authorized agent. A city or county may not conduct an independent sales or use tax audit of a seller registered under the agreement adopted under chapter 57-39.4.

5.    A retailer shall collect city and county sales and use taxes without regard to any cap or threshold on purchases provided by city or county ordinance, resolution, or charter and a taxpayer is eligible for refund from the tax commissioner of the difference between the amount of city and county sales, use, or gross receipts taxes paid and the amount that would have been due by application of a cap or threshold provided by city or county ordinance, resolution, or charter. At the time of purchase, a retailer may provide to the purchaser a credit or refund equal to the refund amount eligible from the tax commissioner under this section, provided the total tax identified on all invoices, cash register receipts, or other sales documentation is an amount equal to the total tax calculated less the refund or credit provided.

6.    The tax commissioner may adopt rules to implement this section.

7.    The tax commissioner may offset future distributions of a city’s or county’s tax imposed and collected under chapters 40-05.1 or 11-09.1 if there was a previous overpayment of the tax distributed to that city or county. The tax commissioner, after consulting the appropriate local political subdivision, may determine the offset amount and time period for recovery of the overpayment of the tax distribution.