(e) If the obligor requests a hearing, a hearing date shall be scheduled within 20 days of the filing of the request with the court.
The clerk of the court shall provide notice of the hearing to the local child support agency and the obligor no later than 10 days prior to the hearing.
(1) If at the hearing the obligor establishes that he or she is not the obligor or good cause or an alternative arrangement as provided in Section 5260, the court may order that service of the order/notice to withhold income for child support be quashed. If the court quashes service of the order/notice to withhold income for child support, the local child support agency shall notify the employer within 10 days.
(2) If the obligor contends at the hearing that the payment of arrearages at the rate specified in the order/notice to withhold income for child support is excessive or that the total arrearages owing is incorrect, and if it is determined that payment of the arrearages at the rate specified in this section creates an undue hardship upon the obligor or that the withholding would exceed the maximum amount permitted by Section 1673(b) of Title 15 of the United States Code Annotated, the rate at which the arrearages must be paid shall be reduced to a rate that is fair and reasonable considering the circumstances of the parties and the best interest of the child.
If it is determined at a hearing that the total amount of arrearages calculated is erroneous, the court shall modify the amount calculated to the correct amount. If the court modifies the total amount of arrearages owed or reduces the monthly payment due on the arrearages, the local child support agency shall serve the employer with an amended order/notice to withhold income for child support within 10 days.