My divorce court order reads that my ex is to pay child support until my child turns 21. My child turned 21 two months ago. My child is still in college full time (3rd year). CSU is still collecting and my ex is still paying CS. Is it my ex's responsibility to take me back to court to point out my child is now 21? Will I have to pay back money for the time since my child turned 21 or will it be based on when my ex files a petition to stop paying? I called CSU but they told me they couldn't answer my question and that I should ask a lawyer.