Dirt and Peeling Off in Window Tint

I sent my Mercedes-Benz E240 to them to have the windows tinted. A few days after the tint settled I found dirt in the window tint which causes bubbles. They seem to have a lot of excuses on why there is dirt in the window tint and refused to apply a new tint. They blamed the vehicle age and "welding" - my car is an original one owner vehicle with no accidents and welding! The tint also began peeling off at the corners of the windows. I have been in the Motor Industry for 20 years now and I appeal to the public to stay away from these guys.