My ex wife never was in compliance with the divorce decree

I was divorced more than 2 years ago, and we had a minor daugther that become and adult last year; My ex had the custody and I had visitacion rights, everything was OK untill March 06, my ex filled a restriccion order in behalf of my daugther; My daugther accused me of been sexually molested by me, we went to court and I keep silence before the judge, so the judge gave me a restriccion order, right after that I had the sheriff detective investigating the allegations and he did all the investigation and found nothing more than just allegations, I keep paying child support untill she was adult, that was in July 06, but in the divorce decree was a line that said that I will pay child support untill her graduation from collegue, after more than a year that I stopped making payments because I did not know if she graduated from High School or was enrolled in collegue because they practically disappear, not knowing where they live I was not able to know if she was in collegue, suddenly and after more than a year I receive a letter from the court stating that I am behind in my payments. The divorce decree clearly state that she (my exwife) had to provide me with the new address. Also, she never delivered some legal papers from some properties that belonged to me as stated in the divorce decree. What can I do?