I think let original shop retry...doesn't seem like much to lose if I'm understanding you correctly. Esp if you have to pay a hefty chunk of change for another shop to do it anyways. If 2nd try at original shop doesn't work out, then would just pay a different shop to do it.
Personally, at no point would I involve lawyers for something like this as the post above says. Just wouldn't be worth the hassle and you'd just be throwing away more money. Unless you are really set on making your point...
Good luck either way though.