I can sympathise where you are coming from. The standard of service is absolutely shocking.
In just the last 12 months I've had:
* A main dealer scratch my alloy severely when fixing a puncture and deny it then send me away with the wheel supposedly sorted, unbalanced!!
* A tyre fitter score my wifes alloy on the outside trying to get the weight off on the inside!!
* A different tyre fitter that changed both my front tyres score the inside of my alloys again trying to get the weights off, plus the machine that holds the wheels obviously never had any protective cover on its jaws so has gouged out 3 bits of the inside of both my alloys!!
* Only last week at my last service have the main dealers scratched all my tailgate then surprise surprise deny it was them. I specifically asked them not to wash the car and they did!!
I've got to the stage that any work I'm getting carried out I will specifically ask them if they can do it without causing any damage and invite them to inspect the car first so they can't deny it was them.
It is so sickening how folk just don't give a shit any more