What to do when you think somebody won't gift?

I just recently won a giveaway, and I'm fearing the creator of the giveaway isn't going to give me the gift. It's only been 2 days since the giveaway has ended, but I've tried sending him a friend request to thank him for the giveaway and he blocked communications. He has also been online many times since the giveaway, so it's not like he hasn't signed in for awhile. I'm not the most optimistic person, so I'm having little faith that I will actually receive my game. What should I do?

EDIT (Including my posts from below for those who don't like to scroll down):

"Yep, it's fake. I sent him a message (joined a group he was in and was able to send him a message) and when I asked him about it, he went offline. Awesome."

"Here's my encounter with him. The trade request was sent to see if he was online or just idle. Since he declined the request, it meant he was actually at his computer and had to decline it. http://i40.tinypic.com/2nlr4h3.png"

"Also, he didn't quit out of Steam, thus removing the possibility of a coincidence. I can tell because when somebody switches their status from Online to Offline by themselves, as in not quitting out of steam entirely, the "Last Online" area of their Steam Profile is incorrect. Instead of showing "1 minute" as it should have, it said something above an hour."