The Commissioner may delegate authority to conduct any administrative hearing pursuant to this chapter to a duly qualified hearing officer. The hearing shall be held upon reasonable notice to the obligee and the debtor. In no event shall such hearing officer be legally competent to render a decision as to the validity of a court order or a defense of nonpaternity. A decision of the hearing officer shall be in writing and shall set forth the debtor’s and payee’s rights to appeal the decision of the hearing officer to the appropriate circuit or juvenile and domestic relations district court. The decision shall be served upon the debtor in accordance with the provisions of § 8.01-296, 8.01-327 or 8.01-329, mailed to the debtor at his last known address by certified mail, return receipt requested, or provided by electronic means, or the debtor may waive service of the decision at the time of the decision. A copy of such decision shall also be provided to the obligee. Such decision shall establish the liability of the debtor, if any, and the validity of the administrative action taken. Action by the Commissioner under the provisions of this chapter to collect such support debt shall be valid and enforceable during the pendency of any appeal. The Commissioner may file and serve liens pursuant to §§ 63.2-1927 and 63.2-1928 during the pendency of the hearing or thereafter, whether or not appealed. Further action under § 63.2-1929 may be taken prior to any hearing or appeal. If the decision is in favor of the debtor, all money collected during the pendency of the appeal shall be returned to the debtor in accordance with procedures adopted by the Board.