Except as provided in subsection (b) of this section, a retail service station dealer may not sell motor fuel below cost. A retail service station dealer may sell motor fuel below cost if the sale is: made in good faith to meet competition; made as part of a final liquidation or closing of the business of the retail service station dealer; made as part of a bona fide charitable promotion lasting no longer than 2 days; or made under the direction or order of a court or government entity. If the Comptroller receives a complaint in writing that a retail service station dealer is selling motor fuel below cost, the Comptroller shall investigate and determine within 3 business days of the receipt of the complaint whether the allegations contained in the complaint are true. The Comptroller shall issue a stop sale notice and may suspend or revoke the certificate of registration of a retail service station dealer if the Comptroller determines that the retail service station dealer is in violation of this section.