Before the Commissioner refuses a license or suspends or revokes any license, he shall give the applicant or licensee ten days' notice, by registered or certified mail or statutory overnight delivery, of a time and place of hearing. At such hearing the applicant or licensee shall be privileged to appear in person or by or with counsel and to produce witnesses. If the Commissioner finds that the applicant or licensee has committed any violation of this article or any of the rules or regulations promulgated hereunder, the Commissioner may refuse, suspend, or revoke such license. He shall give immediate notice of his action to the applicant or licensee.