The Director may refuse to issue or renew, or may suspend or revoke, a license for violation of any provision of NRS 555.235 to 555.249, inclusive, or any rule or regulation adopted under NRS 555.243, but no license may be refused, suspended or revoked pursuant to this section until the applicant or licensee has been given the opportunity to appear at a hearing. Offenders must be given 15 days’ notice in writing. The notice must indicate the offense and the place of hearing.