Research! Look up to see if they're a member of the Better Business Bureau. Even if they're NOT a member (which kind of says a lot right there), the BBB still often has some interesting info on complaints received. I've had occasions where I looked up a business on the BBB to see what I could find out. I did this with the auto shipping companies I was considering. That's one reason I found D.A.S. to be the best choice.

Anyway, if you find they have a bunch of complaints filed, you'll get to see how they were resolved (if they were a BBB member)....it will show if the shop failed to respond at all, or resolved it to the customer's satisfaction, and that sort of thing.

If they have a ton of complaints on file, or a history of not responding, you can pretty much predict what kind of response you're going to get.

You can also cite the BBB in conversation with the owner....yeah it's kind of
blackmail like TREKker mentioned, but it's really the only leverage you may have.

I've got the time if you want me to look up some BBB info I'd be happy to, just PM me name of shop and city.