Hi, did you have all 12 cards? When you get the last card, there should be popup dialog telling you to go see Shawn. Did you have the dialog? If you didn't have the dialog, the game will still consider you didn't have all the cards. This might happen if you try to get the last card at 11.45 pm. If you've confirmed you've got all 12 cards but the game didn't ask you to see Shawn, you need to reload your saved game. Don't try to find the last card at 11.45 pm.