Is this shop responsible?

I had a hub embly replaced on my car and about a week later the tire flew off while I was driving. No one has worked on my car in a long time other than this shop. There were no lug nuts to be found! We found the tire, took 1 lug nut from the other three tires and pulled out the quarter panel for me to get home. Tried speaking the the owner of the shop and I was told "It's not my problem....do what you feel you need to do!" He had many excuses...said that the bad lower control arm caused it...bad bearings and also the "cheap" part that I brought him to put on caused it. But these parts are still on my car and I am able to drive it. What do you think? Is this shop responsible??