Admended Child Support Order- Overpayment

In April 2000 I was ordered to pay $550 in child support, as of August 2000 I owed $900.
Sept 2001 I received an order for child support plus $100 in past due support.

I did pay in 2001 yet still had some overdue from 2000.
Around or before January 2002 the checks were taken out of my account automatically plus $100 per month in owed. It has been at least 9 years I have paid my child support and $100 in back support. In 2010 I started getting $100 checks for over payment which stopped September 2010. I retired and my employer was served with the original order of September 2001. I am again paying $100 extra.

I know I did not owe $11,300 in back support, I know I over paid. What do I do to stop this and how can I get overpayment of child support.

I would suggest you contact your case manager at child support enforcement in order to address this issue.