Won a second copy of a game

Mark the second one as not received and leave it at that, it's all you can do.

For God's sake, please, there have been sooo many threads about this issue already. Don't you know that there is a search function in this forum? You're not a new user.
Sorry, don't wanna be offensive, but it's tiresome to read the same headline day by day by day by day....

Activate one and mark it as received, however leave second one alone, don't touch key, contact giveaway creator and let him/her know that he/she should re-roll second one.

You should not use the key (use or regift), in case the reroll happens at some point. Unfortunately that is up to the gifter and cannot be done by the winner requesting it alone.

You should also preferably leave the feedback pending, if possible.

Closing thread.