Hello Shiron,

Let me quote the FAQ:

When should I mark a gift I won as "Received" or "Not Received"?

• You should only mark a gift as "Received" when you have both (i) received the exact game described in the giveaway, and (ii) activated that game on the Steam account you used during registration. In all other instances you should mark the gift as "Not Received" one week after the giveaway has ended.

if the game has not arrived

If you didn't get the game, you should remove your positive feedback. Please click again on "received".