Parole revocation and restitution

I have theft by unlawful taking charge over 300.00, originally received probation but fell behind on payments and was revoked. Spent 22 months of 5 year sentence. My max exp date was 6/11/07 and probation parole keep telling me I will not be off until rest pd in full. Now I lost my job 8 months ago and have fallen behind again and have a hearing to revoke. Can they do this now? I have been researching the law and it is so confusing. One law says they can extend until pd but another says a person cannot be held past exp date. Not to mention the ex post facto clause.