Large overpayment of child support

I will try to make this brief as possible husbands info
2002 order started for amount of 875/month based on 15.25 a hour for 4 children (plus ins)
2007- move to Florida to take care of in laws take a job making 8.50 a hr, sent new info in to NC child support, Hendersonville, called several times, sent letters nothing changed and no response- 3 children now still suppose to pay the 875/month
2011- Florida was taking his drivers licence - (they where taking 55% of his checks) Florida court told us to figure out the NC part it wasn’t their job to do it
I printed out the form I found on a board, whited out their info put in husbands info into paperwork (courts would not send me modification papers in the mail) and mailed it in
got a mod meeting in 07/2011 now down to 2 children and making 9.00 a hour (456/month) 8k was taken off because the second child had been out of house since 2010
2013 oldest remaining child was taken off, active children now 1, still no change in amount
requested another meeting in 2014 (10.00/hr pay 1 child) sent letters, called and got no response (come to find out worker and ex had breakfast the morning of the last meeting to discuss the case I asked to have a judge review it and was told no, she was the person who did that)
now (2016) pay is 15/hr ex says she is going to request more child support (still paying 456/month- child arrears down to 2500)
youngest child will be 18 in Dec but attends school till Jan
when figured all up using the NC child support worksheets we have overpaid thru the years 28k…what can we do???

oldest child was suppose to be taken off at the end of 2007 (18 not going to school and moved out)

Any time there is a substantial change in circumstances (change in pay, change in custody schedule, children age out, etc.) the best way to change your child support amount is to file a motion to modify child support. I understand it was difficult to handle this while living in Florida, but North Carolina has control over the current child support order, and so long as the children live in North Carolina, North Carolina is the proper state to make any modification. Any modification ordered will be retroactive to the date of filing your modification. As you seem to be having a problem working with child support enforcement, I would consult with an attorney in the county where the child support order is currently active and discuss your options.