2 things :

1- If the item is currently in the game, then it's the DM that have put them there in the first place. It's fine to take them away if you made a mistake, but it's your mistake, better own to it. 2- This is hilarious as I just gave my players a blank check where they can get any item whatsoever. Only one. But I'm waiting with excitement on what they will end up with.