Any liability a parent may have for employee contributions required under the plan for enrollment of the child is subject to appropriate enforcement unless the parent contests the enforcement based upon a mistake of fact, except that if enforcement of both the full amount of cash child support and the full amount of medical support violates the application provisions of 15 U.S.C. § 1673, Section 303(b) of the Consumer Credit Protection Act, then the current month's cash child support shall receive priority, and shall be deducted in full prior to any deduction being made for payment of either current medical support or health insurance premiums. If the employee contests the withholding in the manner prescribed within the notice, the employer must initiate withholding until such time as the employer receives notice that the contest is resolved.