Hey guys. I'm new to the forum and thanks for having me.
Now to my headache of a problem.

So I've had the car for just under 2 months now. 07 Audi a3 s line. There was wobbling from the back end when going over 50mph and hitting bumps. So I've had all the back end done. New arms etc. New shocks on the back also. After getting that done the tyres we're very worn on the inside. So i thought that was the problem now that I've just had all the work done. So I've just had brand new tyres all round and also wheel alignment done.

I take the car from the garage and the cars back end felt like my wheels was being held on by a single nut. That's how bad the wobble was. I couldn't even go over 30mph. So I took it back to the garage. Left it with him. Went to pick it up to be told that he can't get the back left wheel mainly to come in. So I've just got back from the first garage I went to and they've just tried doing it by naked eye due to not having the right equipment to do it. My question is. What can be causing my car to wobble at the back end everytime I'm going at speed? I know its due to hitting bumps on the road and it just feels like the backend isn't gripping. Is it just needing a wheel alignment done? Or could it be something else?

Any help or information would be greatly appreciated guys.
Thanks