A Child Support And A Property Problem! Help Me!!

[diag]

What is the name of your state? FL

When I got divorce my ex and I have a property and children.
at the FINAL the judge set to sell the house 50% / 50% my ex was agree to BUY my part. (my ex is the custodial parent), so I made a deal to pay in full my future child support and arrears with my house's equity, my ex was agree and the court order to the other party to pay me for the remain of the equity (around 6K) within 90 days.

the problem is the 90 days past due and my ex is still not paid me.

also as I said before I paid in full my future child support so the court order to stop the enforcement and the judge said whole money that my ex got since the FINAL must give it me back.

and of course meanwhile the child support enforcement got the court order it took some weeks child support withweld some money from my wages also
the IRS WTHWELD my tax refund for supposed child support owed

my ex took the money and she doesn't want to pay me back
what can I do to CLAIM MY MONEY BACK??

my question is what can I do to Sue her to recover money??

I appreciate your help thanks