But it does not matter. You can't leave incorrect feedback for game, because creator can't get contribution value for game they did not send.

It may be not that visible here (sending game they got for free, and list it as bundled), but imagine someone has key for Tomb Raider 2013, and give it as Shadow of the Tomb Raider. Getting full non-bundled CV and mark for giveaway they did not in fact deliver. Or someone already has TR 2013, and wanted SotTR. So they did not get game they really wanted to play.

Creator of course can give you game as "compensation" for their mistake, but can't ask you to incorrectly mark it as received. And there are no exceptions from "you must activate your win" rule.

Change status of this giveaway, and write in comments that you did not in fact receive game from giveaway. That's only solution to leave this situation "clean".