False info given to dhr

My husbands ex wife filed a case with alabama dhr for child support, at the time she opened it he was in jail for back child support. She had an attorney and so did we. We paid her a lump sum and his payments were modified but she did not tell dhr any of this. All the amounts that dhr is saying he owes is false from back amount to monthly payments. We have also been paying her directly because this is what the judge told us to do. what can we do to get this off of him. We was never served with papers from dhr we found out because it is on his credit report. She said she didn't file it but case worker said she did.