Before things go much farther, post details on the car, we are just making a guess that it is the one in your sig.

Did they do any diagnostic testing?

Did they do any other work?

Did they give you any receipt? ( If not and they charged tax they may run afoul with the state. If they did give a receipt, post it _exactly_ as written. )

Any chance the person giving you the bill was running they own repair while the shop owner was away? ( In this case it isn't the shops fault, rather the employees fault. )