Notwithstanding this part or any other law to the contrary, if the department of human services serves as the central collection and disbursement unit for the state, then the department must establish, advertise and maintain a customer service unit and a statewide toll-free telephone line for the express purpose of receiving and responding to citizen inquiries and complaints concerning child support collections and disbursements. Notwithstanding any law to the contrary, if a contractor of the department serves as the central collection and disbursement unit for the state, then the contractor must establish, advertise and maintain a customer service unit and a statewide toll-free telephone line for the express purpose of receiving and responding to citizen inquiries and complaints concerning child support collections and disbursements.