You can sometimes consult with a lawyer for free at the local family court. Also LIFT online offers some advice. Generally, child support should not be over half your income. You need to move the court for a downward modification. Additionally, if SSI is paying directly to the custodial parent for your child(ren) then you should be getting a credit of that payment as part of your child support.
Good luck.
Answered on Feb 21st, 2013 at 3:25 PM