"I think a lawyer would probably be more dishonest than the plumber."

Well, they certainly cost more. I guess I'm amazed at all these
responses. The OP just paid the guy and found the leak in 15 mins, so
there isn't any huge damage involved, just some wet carpet. He didn't
say how long he's been calling without getting a return call. I'd
certainly give the guy a chance to respond before I escalate everything
into crisis mode. I agree if the job was done right, it never should
have happened. But any of the other avenues, they are going to expect
that you gave him some reasonable amount of time to respond.