(a) The Department may, upon its own motion, and shall, upon the verified complaint in writing of any person setting forth facts, investigate the actions of any applicant, registrant or any person who may be in violation of this Act. At least 10 days prior to the date set for hearing the Department shall notify in writing the person, hereinafter called the respondent, that on the date designated a hearing will be held to determine whether the respondent is in violation of the Act, and shall afford the respondent an opportunity to be heard in person or by counsel. Written notice shall be served personally on the respondent, or by certified mail, return receipt requested, sent to the respondent’s business address as shown in his or her latest notification to the Department.
     (b) The Department, over the signature of the Director, may subpoena any persons in this State and take testimony orally, by deposition, or by exhibit, in the same manner and with the same fees and mileage as prescribed in judicial proceedings in civil cases.