I don't know what to do

Patience young grass-hopper

Wait 7 days.

Wait?

You need to be patient, maybe that user has not been able to check his mails/reply/etc. He might or might not reply.

Some people don't reply at all, which is ill-mannered, but that's how it goes sometimes.

But if he does not activate that game on his steam account within a week (see here ), you could perhaps report him.

Once I decided to abandon steamgifts, and havent loggen in for 2 months. When I logged in, I found out that I've won a game :D
(It was a developer giveaway though) Patience.

Also, don't call out the winner! :p

wait 7 days and give no

Don't call out users, please remove the link to his profile. Just wait patiently, if nothing seems to happen send him an e-mail and ask what's taking so long. Or try to contact him in Steam by adding him as your friend. After 7 days has passed, you may re-roll the giveaway but be careful: you won't know if the key has already been used.