Gift card already redeemed

I am sure this isn’t the first time someone has had this issue. My 11 year old worked his butt off pressure washing driveways and got paid yesterday. Took him to target to let him get a 50 and 25 dollar Apple iTunes gift card. He redeemed the 25 dollar one first with no issue then goes to redeem the 50 and it said the error. We go back to target and they say they can’t do anything but call Apple and they should be able to help. After 25 minutes they tell me the card had been redeemed already and there’s nothing they can do. This is impossible since I literally watched him open the card and try enter it in. So long story short my 11 year old is out his hard earned 50 bucks because of this garbage. I’m so frustrated and he is so disappointed. I really wish apple or target would step up and do the right thing but I guess they could care less.