No User Response

They have up to 7 days, after that just contact staff.
Edit: Also try and remind them on steam, mabey they just forgot.

Wait 2 more days. It says in the FAQ that they have 7 days to respond. If there's still nothing, I'd recommend adding them on Steam to let them know and if they still won't add you, request a re-roll.

What the others said, you also should read the FAQ again.

Try to badger them via e-mail to do it, just a friendly reminder should be enough.

If the 7 days pass, contact support and try to give the key to a friend so they can check whether it's valid or not and, if not, they get a game and you get a good mood.

Yeah I don't think it is on the FAQ (unless it is, I didn't even read it myself). There are some posts on the forum though.

that's why i never send via email. I add the winners on steam if it's a key and ask them to chat with me. That way I know for sure they took the key.