As long as you can prove you paid for the software, I would think using a bootleg keygen source would solve your issue. GR is one of those that I frankly have had a really hard time getting any response. I can't even get OK for the forum even though I have three legit, paid for versions. Keygens are the way hackers get the stuff free, which I don't encourage, but GR is cheap enough to pay for, and will solve the issue of lost keys. I had to do it for one PC game (SimCity4) when I lost the box and didn't write down the serial number on the disk (as a normally do).
BUT, do try to go to the source first. The suggestions to go to GR first is the right one. The Keygen solution is only one of last resort.