The Illinois Department, or any officer or employee thereof designated in writing by the Illinois Department, shall conduct hearings and investigations in connection with petitions filed pursuant to Section 10-12 or Section 10-12.1. Responsible relatives and persons receiving child support enforcement services under this Article shall be entitled to appear in person, to be represented by counsel at the hearing and to present all relevant matter in support of their petitions. The provisions of Sections 10-13.1 through 10-13.10 shall govern the hearing.
     The hearing shall be de novo and the Illinois Department’s determination of liability or non-liability shall be independent of the determination of the administrative enforcement unit.