We managed to minimize our mistakes with our double-check system. The first time is when we buy a code from our suppliers and the second time is just before the table with the codes is generated. We guarantee that there will be no wrong codes. If you receive a message "code already used" inside the game, it means you have already redeemed such a code on your MTG Arena account because all codes have an account limit. If you do not want to give it to a friend, the second option is to write us at [email protected] and send us the code to check it. If it is still operational, we will refund your money to your wallet balance (store credit).