PRO Window Tinting

So I have had my truck in the shop 2 times now for window tinting. The 1st time was Christmas Eve 2008 and then I took it back in again on 3/13/2009 for them to get redone because there was a lot of dust particles in between the tint and the window... The guy told me that its impossible to get rid of all the dust, but he went ahead and redid them for me, and I am having the same problem. I have talked to a few people who have had window tinting from the same place that said they never had that problem....... Today I took my truck to a different window tint place to have them look at it, and they told me, that was NOT supposed to be like that, and it was crappy work, and pure laziness. So I took my truck back to Pro Window Tinting to have them fix it once again, and the MGR said that he wasn't going to do it again. He said since it happened a second time it would just happen again. That was even after I told them about what the other place told me. So then I asked to get my money back because I am completely dissatisfied and he told me that they do NOT do refunds... Now they claim to have a 6 month installation warranty and I have only had the tint on my truck for 3 months today, so its OBVIOUS they do NOT honor their warranty or stand my their work!!! Also, they ONLY ACCEPT CASH payments, and don't give receipts, and they told me when I went in there, that they can say there is no proof that they even did my windows, so nothing can get done to fix my problem.