Multiple win - What now?

Ask for a reroll. But activate the first game.

Leave it unmarked, try to contact the creator.
If unsuccessful, send a ticket to support.

I think you might ask the Creator to re-roll the winner, as long as you didn't use his key. Don't know if it's the right thing thought so don't count only on this comment.

what BushiCowboy said. mark only the first as received and ask for a reroll in the second win as a comment

Try to get the creator's attention by explaining the situation in the giveaway topic and ask him to reroll the second one that you didn't activate.

If you don't hear back in a week, mark as received and then I'd say contact support.

Comment in one of his giveaways, tell him you've won both keys and that he should re-roll one of them.

- don't use the other key.
- reply in the giveaway thread that you already won that game, tell him to reroll.
- try to add on steam.
- don't mark that win as received, leave it without feedback (just deal with the +1 notification on the navigation bar).

Ronix (Moderator)

If you win the same game two or more times you should:

1 Reject the gift: if it's a key, do not use it, if it's a gift you must return it to the previous owner.
2 Leave a comment on giveaway page explaining the issue and asking a reroll. The creator will get a notification.
3 Wait a week, then mark the giveaway as "not received".

This is what support told me to do when I got multiple wins.

Dont use that key
Write a comment on the giveaway page, if he doesn't answer, leave it unmarked
Not the first time this as happen, it's mostly to build awareness to some game, who gets the game or doesnt isnt their main concern