Before denying, revoking or suspending any license under this article, the director shall give notice to the applicant or licensee, specifying therein the specific violations or reasons for the proposed action, which notice shall direct the applicant or licensee to appear before him at some specified time to show cause why such license should not be denied, suspended or revoked. Upon failure or refusal of the applicant to appear or upon findings at the hearing, the director may deny, suspend or revoke the license. All orders or notices by the director shall be served on the applicant or licensee by certified or registered mail at the address shown on the application or by personal delivery. If the applicant or licensee cannot be found, it shall be sufficient to serve any person in charge of the enterprise at the premises or to post a copy of the order or notice on the premises. (Mont. Co. Code 1965, § 75-11.)