Won giveaway without gift

Yep mark it as not received.

You sure you don't have it in your inventory?
You maybe clicked on it and received it, and it goes into your inventory
Also the gifter has 7 days to give you the game, so wait those days, contact him or mark not received

http://www.steamgifts.com/about/guidelines

• Allow the giveaway creator one week to send the gift. Please be patient and do not contact them during this time. If the gift is not received after one week, you may contact the giveaway creator on Steam to follow-up.

Done that, now will anything happen?

Go talk to him and see what happens. Give it a week.

Maybe since you blocked them,they decided for a re-roll or maybe gave it to someone else

I think if your going to be using this site it might be best to check who it is and who it might be before blocking them,adding someone will not do any harm as you can always block them if you find out it is some random idiot

Does it still say you're the winner? If the gift was activated by someone else, (s)he still have 1 week to give you the goodies you rightfully won

EDIT: Oh, didnt realize this thread was a week old. just ignore this please, also, if the creator really did re-roll, you shouldn't really have the option to choose received and not received right? That means he didn't re roll for a new winner

Yes, I am still the "winner".