If your rights are involuntarily terminated, you cease to have any rights or obligations, including the payment of birth expenses or child support, to that child. If you owed support at the time of the termination, you still owe that support - it doesn't wipe out any arrears.
With that said, the state has an interest in collecting birth expenses, not mom. I suppose they could argue they should have been notified of the TPR and had a right to object. However, absent that, I believe they are out of luck. There isn't any specific statute or case law on this - it is just my analysis based on other statutes as applied to your fact situation.
You should hire an attorney to make these legal arguments on your behalf in the motion by the state. Perhaps they aren't even aware of the TPR? They wouldn't automatically know about that and should be informed.
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