The Department may investigate the actions of any applicant or of any person or persons holding or claiming to hold a license. The Department shall, before refusing to issue or to renew a license or disciplining a registrant, at least 30 days prior to the date set for the hearing, notify in writing the applicant or licensee of the nature of the charges and the time and place that a hearing will be held on the charges. The Department shall direct the applicant or licensee to file a written answer under oath within 20 days after the service of the notice. In case the person fails to file an answer after receiving notice, his or her license or certificate may, in the discretion of the Department, be suspended, revoked, or placed on probationary status, or the Department may take whatever disciplinary action deemed proper, including limiting the scope, nature, or extent of the person’s practice or the imposition of a fine, without a hearing, if the act or acts charged constitute sufficient grounds for such action under this Act. At the time and place fixed in the notice, the Department shall proceed to hear the charges, and the parties or their counsel shall be accorded ample opportunity to present such statements, testimony, evidence, and argument as may be pertinent to the charges or to their defense. The Department may continue a hearing from time to time. The written notice and any notice in the subsequent proceeding may be served by registered or certified mail to the licensee’s address of record.