No problem, it's not your fault and I know such things happen. With developers revoking the keys left and right lately, it's expected that such incidents will happen more often. If you want to you can send e-mail to groupees and ask them for resolving this situation, since if you're sure that you didn't trade/activate that key, then there should be no problem in revoking it and generating new one, since you paid for that.

But if you don't want to bother with this, you can ask the SG support for giveaway deletion, and since I agree to that as a winner, they should make you no problems.

Thanks for whitelist, have a great day!