Had a similar thing happen about 15 years ago with my mom and her Older caddy, Dave. Went in for brake checkup and an alignment, next thing is the exhaust is f-d up (They grabbed it with a huge pair of water pump pliers and ruined the pipes and mufflers in the process, that'was how they "tested" them). Among other things they replaced.
My mother goes to pick up her car and they say "$1650" or something like that. Calls me in tears. I drove an hour and a half from Ohio to PA to confront this shop, and here the shop manager was a guy I went to high school with, and shoulda known my Mom.
Pipes and mufflers they destroyed were fine, as far as I could tell once they finally let me see them, brakes were OK as well, really didn't need them yet, or new rotors, wheel bearings, all the crap they threw on there. Ball joints, tie rod ends, etc were all fine to me. (Took me an hour to get them to ressurrect the old parts for me to inspect, and here they didn't change out the ball joints at all anyway, even though it was on the bill)
The guy ended up not charging my mom a nickel for anything, as when he was talking with his District manager, I was in the lobby telling people to get their cars out of this shop like NOW, or they'll be ripped off too. And they were.
I still see him from time to time when I travel back east, but he avoids me. Always thought maybe I was too rough on the guy, but hey, that was robbery as far as i was concerned. These chain shops are rediculous. Find a mechanic you trust, independant, and go from there. Support local business I say.
Ray