The director of environmental management shall issue to an applicant, on payment of twenty dollars ($20.00), a license entitling the applicant to conduct the business of buying milk and cream from producers for the stated purpose at an office or station at the place named in the application until the first day of July; provided, that if the application is presented in the month of May, and if the applicant elects, the license may be granted to begin on the first day of July and run for a term of one year. A license shall not be issued to any applicant if, during the year preceding the filing of the application, a complaint from any producer and seller of milk or cream has been filed with the director against that applicant for any of the grounds specified in § 4-8-14, and that complaint has been established as true and just, to the satisfaction of the director, after the complaint has been investigated by him or her in the manner provided by § 4-8-12 and § 4-8-13.