Can an auto repair shop charge for storage if no work was ever done to the vehicle?

Question Details:

Took car to mechanic to have engine replaced. He had done other work for us. We found out today this guy doesn't own the shop like we thought. The real owner won't let us have the car. We owe for storage he say - $3,000s. There was never any work done on the car. I didn't think they could do that unless the work was finished? Important Notice