A shop shall return to a customer, upon reasonable demand, the customer's repaired motor vehicle or appliance if the customer pays the shop's bill except the proportion of the bill which represents:
(a) repairs, service calls, or estimates which were performed but not authorized;
(b) charges for service calls or for making estimates which exceed the charges disclosed to the customer prior to the service call or estimate; or
(c) charges for repairs which exceed 110 percent of charges authorized for repairs by the customer pursuant to section 325F.58, subdivision 6, plus 110 percent of the sum of the total prices in written estimates given in connection with repairs. Nothing in this section shall be construed to authorize repair charges in excess of reasonable charges for parts and materials and labor.