This is not fair to the parents who use the services of the private agency. No business should require a customer to continue to pay for a service that is not being provided. An agency is going to be limited as to the total amount that it can collect from a non-paying parent toward arrearage. What limits the amount that can actually be collected is going to be linked to the financial abilities of the obligor as well as various laws. If the agency is obtaining the maximum amount that can be paid, there is no reason why the agency should continue to take a percentage of every dollar that is paid.
Advertising is expensive.
The more expenses that a private agency has, the less effective it is going to be. Parents who are delinquent in their child support are usually not going to agree to pay the arrearage plus interest that has accumulated over the years. In most cases, for the agency to receive maximum results for its clients, the non-paying parent is going to have to be taken back into court. This is a fact of life. There is no way around this.