I'm really not sure what's going on - it's had three people there try it, and I repeat, I've never had an issue with them in the twenty odd years I've been using them. I'm not the sort to throw away a previously satisfactory business relationship that easily.a tyre fitter hasn’t balanced the wheels properly.
The one thing I'll throw in is that it does get harder when wheels are bigger, and these are 19" ones. Not that this is an excuse - they've fitted several sets to the RS4 before without issue. Fingers crossed that starting from scratch will sort it.