Just a tip:
Only mark a game as received when you successfully added the won game to your library. Otherwise this could end up in a temporary suspension for you.

I agree with klinge. If you didn't get the exact game you need to remove your received mark.
Just go here http://www.steamgifts.com/giveaways/won and click the green thing that says received so it's no longer green. If he hasn't come up with the actual game in seven days you'll be able to mark it has not received.