in sept 2012 a final order was written for time sharing and child support, nothing in this stated anything in regard for back child support from before the final order date, now my ex is taking me to court asking for back child support, in florida where the case originated, does res judicata and estoppel prevent her from being able to get back child support since it was not written in the final order and the appeal time has passed????
Not if the issue was never raised in court.
If not referenced in the final judgment nor reserved upon by the court in the final order, then it is waived.