Permits may be refused, suspended or revoked by the “secretary” if, in his judgment, the requirements of this act, and the rules and regulations made in conformity herewith are not complied with by the person making an application for a permit, or to whom a permit has already been issued.

Before refusal to grant a permit or before a permit is suspended or revoked, the secretary shall afford the applicant or holder of the permit an opportunity to be heard, and shall give at least five (5) days written notice of the hearing to the applicant or the holder of the permit, by registered letter sent to the address given in the application.