So you tried emailing Gainward 2 years ago with no luck and thats it done with trying to contact them via email?
You may have no joy but you have options, trying usually works.
I have had to return a £3k projector twice now within warranty and the first time time they refused to repair within warranty but after much discussion with the shop I purchased from they footed the £1.5k repair bill. 7 months on and its back in for repair for the exact same issue, except I told the shop I didn't want to deal with the PJ manuracturer, as such the shop themselves have sorted it. I don't know if they paid anything again but i'm still getting it back free of charge because I stuck my ground and asked without any legal advice.