Complaint Review: Charlie's Tire Center

I've been a loyal customer to Charlie's Tire Center for many years and the service I've recieved was reasonable until I took my S10 to have the driver side seal on the rear axle replaced. After taking my truck there, I waited and waited and waited. Periodically I would walk to the bay door to check up on it. One time, one of the guys said that another guy messed up something and was taking the inner shaft to a grinder. I thought it was no big deal as long as it's functional after they're done. After getting it back, I heard a high pitch grinding noise coming from the truck and when I got home, I checked under the truck and the seal that they replaced is leaking. I called and informed them about the leak and the noise and they said they'd be happy to fix it for no charge. Took it back the following day and they found a problem with the parking brakes on the driver side (which would initially start this problem). They replaced that and the seal. I don't think they test drove it because I still had that noise when I got it back. In the end, something in the rear differential snaps and sends a big chunk of metal THROUGH the differential cover. After all that, what should have costed me no more than $300 for 1 seal and driver side parking brake assembly, costed me almost $2000 (seal, parking brake assembly, and a used rear axle). What burns me is that I can't get that money back because I can't prove they done it. And I know it would be cheaper and make more sense if I do my own mechanical work so that I don't have this problem, but they had been reasonable before, and I lost all my mechanical patients when I bought a somewhat updated vehicle.