Seems that your tint shop is not as professional as you think.
If this was a potential problem, he should have told you ahead of time.
I call what he said as "after-the-fact bull shit".
Is there a warranty with your install? did you get it in writing?
What's the labor warranty?
If this happens to other people, how come I haven't seen it posted before on the forum.
If your tint shop doesn't fix it, then you may have to sue him in small claims court.
His labor or the material is defective.
2004 E60 530is, Delivered 12/12/03, TiSilver/LGrey, PP, SP,PS, PDC, ACC, FRS, Step, Xenons, clear bra, body colored rear inserts. (Retired, 1983 henna red 320is)
2004 Corvette Z06 Commemorative Edition