They will evaluate these things once a month and your husband should get a check back. Just keep calling them.
My husband changed jobs, and it took a while for the state to start taking his child support out of his check. We were sending the state the money by personal check on his paydays. After I had already sent the check from that pay period, the state took the child support out of his check for the first time. Now, we are ahead on our child support, but behind on my car payment because of this. The clerk of court refuses to talk to my husband, and no one at child support enforcement will allow us to skip a payment (It’s taken out automatically) to make up for the overpayment. How can we get this money back?