The windows CAN be polished with a buffer just like the paint. The one drawback to that and probably the reason the glass shops said there wasn't a solution is because doing so will change the glass. the glass will develop a "pit" or for lack of a better way to describe it, a crater in the glass that will change how things look when you look through it. I have had scratched in front of the driver on the windshield that I had to leave because polishing them out would have distorted the view through the windshield. But on the side windows with tint, I would guess that it wouldn't be as noticeable as the scratches themselves. Good luck getting it worked out.
