horribly botched tire change

I brought my car there to have my existing tires put on my new rims. I was quoted $40 for the job which seemed low but accepted. An hour and a half later the job was complete and I was informed that it would now cost $79 because the job took longer because I have runflats [tires are all marked runflat and the job was quoted with my car present]. I agreed to pay figuring that I knew it should be more anyways and left. The following day my tire warning sensor went off. After checking the pressure they were dangerously overinflated to 40 psi instead of 32 psi and the steering wheel was shaking on the highway. I took it in to a Mr Muffler to have the mounting and balance checked. The wheels were mounted without the proper fitment disks and should have never been put on. They damaged the sidewall on one of the tires when forcing it on or off and the tire is ruined, and the wheels were balanced with 4oz weights when only 3/4 of an ounce was required. Tires are their specialty and one of the more remedial repairs you will ever have. If I did not understand my car, sense the change in the drive and fixed the problem right away, it would have likely resulted in my tire blowing out or more permanent damage that would have been far more costly. They are a disaster and as was the experience.