The time to challenge the allegations as to whether the drugs were yours or not passed by a long time ago. You were convicted of possessing the drugs, that makes them yours. My best guess would be is that there is an active warrant out for your arrest for having violated your probation based on your failure to report as ordered. You are potentially facing a period of incarceration equal to whatever the maximum sentence was for the original offense. If you want a chance of being shown any consideration whatsoever, you need to go hire yourself an attorney now and make arrangements to get yourself turned in on the probation violation warrant.
This could turn in to a serious mess for you. The previous poster is right; the time for challenging the case has come and gone. The only way to get the probation is to have plead guilty. If and when the state adjudicates you on this case, they won't be asking whether the drugs were yours. And they won't give you the opportunity to claim they weren't. All they'll be asking is whether you've complied with the terms and conditions of your probation. Clearly, the answer to that is no. You really need to hire an attorney to advise you of the best way to handle this situation. If not, you'll always be looking over your shoulder for a Sheriff to execute the warrant that is surely out there, and take you to prison. Typically, the longer you're on the run from it, the less sympathetic the judges will be. Best of luck.