What are my rights if my car was at a body/paint shop but it burned down and my car was totaled?
Question Details: Is there anything I can do to recoup my car? I signed a paper relieving them of responsibility for any damage.
If you have relevant insurance (e.g. "collision" coverage), you can, of course, submit a claim to your insurer. Otherwise, you might not have any recourse or options:
1) If you signed an agreement relieving them of responsibility, that waiver of liability may be enforceable, as would be any other contract. (Whether it is enforceable or not can only be answered definitively by an attorney reviewing the exact language of the agreement and the precise circumstances.)
2) Even without that waiver, they would typically only be liable if they were "at fault" in some way in causing the fire and/or destruction of your car; people and businesses are generally only liable, or financially responsible when they did something wrong (for example: used welding or heating equipment improperly, causing the fire).