If the Court is saying you violated the terms and conditions of probation then you need a lawyer. A lawyer can investigate and bring proof to the Court that you did in fact comply with the terms of your probation
If they are saying that you have violated probation, and they are filing a motion to adjudicate / revoke that probation, then you definitely need a lawyer. There must be something else amiss - perhaps a meeting LONG ago that you missed or some other violation because the probation officer would have called the rehab to check on your status (and not just depended on missing paperwork.)
Many times they wait until just before the person is about to get off probation to file alleging long ago violations. They do this so they can get the judge to extend the probation, or at least not terminate successfully. If this is happening, you also need a lawyer because you want your probation to be satisfactorily terminated.