Won a giveaway, the key was already redeemed

just click not received

Leave a comment on the giveaway or contact them through Steam. Don't mark the game as received until you actually have it.

You can comment on the giveaway page - creator will be notified.

You could try commenting in the giveaway comments or add them on Steam. If that turns up nothing then open up a support ticket and/or mark as not received.

You can post on their profile on Steam or try to add them as friend (but the latter might end up in them blocking you). Then explain the situation. If they agree to send the right key, all's well. But if they offer you a different key, even for a better game, you cannot accept it. You need the game you won REDEEMED on your account otherwise you might be suspended.

I marked as not received and left a comment on the GA. I'm sure it's just a mistake. Thanks, all!

Based on the feedback from this post I just unchecked received and not received. Now it's "awaiting feedback".