Scared and confused ?

my estranged husband and i are still married, before i moved to N.C., I took him to court for child support in 1995, we were married in 86, he cheated so i took the three kids and moved now my children 22, 19, & 16. i just moved back to fla in march he was ordered to pay $174.00 a week in 95 and i never took him for incrasments ever! anyway my 16 year old went to him on fathers day the following monday i was servrd with divorce papers, and he wants full custody with me having visitation, from what the order says is that my support payments was only temporary, and that it expired in 98, and now saying he wants to be reimbursed for over payment i am so confused and now he wont let me even talk to our son, now 16. he never paid for the kids to visit him the whole 13 years i lived in NC, and only sending them $50 birthdays and the same at christmas. can he do this the state of fla took his money every week and sent them to the NC child support, i still receive ch supp can not afford lawye