Then follow what LdiJ said here. The collection agency has to prove it's your debt in order to legally collect from you, they can't since it is not your debt.
You may be responsible for a portion of the medical bills per your child support order. But your ex needs to take that up with family court.
There is a provision for both parties to pay a portion of uninsured health care cost. Per form FL-192 in my order the law says:
Disputed charges. If you dispute a charge, you may file a motion in court to resolve the dispute, but only if you pay that charge before filing your motion. If you claim that the other party failed to reimburse you for a payment, or the other party has failed to make a payment to the provider after proper notice has been given, you may file a motion in court to resove the dispute. If the charges were paid then the court would find the charges reasonable.
He has never given me proper notice, an itimized statement of the charges within 30 days after those costs were given to him. The bills are from a year ago. If he had given me proper notice then I would have 30 days to pay either him or the company.
Now he wants me to deal with the collections company and has given my info to the collections company. According to his email he has not made any payments either. I did not know these charges existed until a few weeks ago when he emailed me the names of the collections agency and told me to call them to take care of it.