If the commissioner refuses to issue a license he shall:
(a) Notify the applicant of the denial and of his right to request a hearing within 10 days;
(b) If the applicant does not request a hearing, return the sum paid as a license fee;
(c) If the applicant requests such a hearing, give notice of the grounds for refusal and hold a hearing thereon, and within 30 days after such hearing the commissioner shall file a written decision containing his findings and conclusions and serve a copy thereof upon the applicant.