What should i do?

You should mark it as "not received".

Please remove the last screenshot.

Edit: the winner could request the deletion of this giveaway, but he needs your agreement.

Let the creator of the giveaway know that the key was already used and that you'll have to mark it unreceived after 7 days if he can't give you a working copy.

Contact the person who hosted the giveaway and inform him/her about the problem. If the person does not give you a working copy of the game, mark it as not received in 7 days.

1st off edit GA creator nick and avatar out of image or you may be banned for calling out.

then do what other suggested

What does that last screenshot have to do with anything, is he forbidden to own the game he is giving away?

Mark not received in a week. You can also try to contact the giveaway creator in case he made a mistake.