Duplicated code.

Yes, you can wait 7 days and mark it as not received.

No, you can only mark the game as "not received" once 7 days have passed.

You can also talk to the gifter. He has 7 days, if he doesn't give you a key, message support providing proof.

http://www.steamgifts.com/support

tente falar com o cara que fez o giveaway, se não resolver marque como "não recebido", não tem muito o que fazer :/

Either reply to the email he sent you, or message him on Steam saying so.
It might have just been a mix up with the keys.

Hm, thanks guys. I sent email, but he did not answer.
First I won :/