2. Done work you did not authorize;
3. Not fixed it correctly.
In Rhode Island, a repair shop generally must return your car – even if you have not paid the repair bill – unless the shop has an authorization ok’ing the costs of the repairs signed by the car’s owner. (The law is RIGL 34-32-1.) In my experience, repair shops seldom have that so, if they keep it, I believe they are guilty of civil, and possible criminal, conversion.
Getting the car back does not mean you do not have to pay; once you have the car, the shop can sue you for what it believes you owe.
If a Rhode Island auto mechanic is holding your car hostage, consider: a) Asking for it back in writing – by fax, e-mail or overnight letter – so it is clear you want it; b) Filing a police report if the shop will not return it; and c) Hiring a lawyer. If you cannot afford one, consider suing the shop in Small Claims Court.