The department may, upon its own motion, and shall, upon the sworn complaint in writing of a customer of a collection agency, investigate the actions of a licensee claimed to have violated this chapter and, for that purpose, shall have free access to the offices and place of business and, if the complaint involves customer accounts, to all pertinent books, accounts, records, papers, files, safes, and vaults of the licensee or certificate holder. If the complaint involves the owing of money, or any other thing of value, by a licensee to the complainant, when the licensee raises the issue of an offset or counterclaim, the department may require the complainant to submit all records and data in the complainant’s possession pertaining to the offset or counterclaim.