Call your state bar association and get a referral for a local attorney, a lot of state bar associations offer 30 minute consultations for >$50, and at the very least give you advise on how to proceed. A lot of times a demand letter sent from a lawyer is enough to get them to release the car and waive whatever bogus fees they're charging, and if not off to small claims court, where again they can advise you how to proceed or even handle it themselves if you'd like.