My Apple gift cards has been hack

You are likely the victim of gift card draining.

https://www.staysafeonline.org/articles/avoid-gift-card-draining-scams-this-holiday-season

Apple can't do anything about it. If you, or someone else bought it for you, go to the store the card came from and try to get your lost funds from them.

See this article:

About gift card scams - Apple Support

Did you purchase a Gift Card off a rack that is available for anyone else to tamper with the cards? If so, don't do that. Ironically some of those same retailers will lock up products that could be stolen from them, but when it comes to their customers losing money, they display those out in the open. Only purchase Gift Cards where they are secured behind a counter. That is true for any Gift Card including Google Play and any other store branded card.

Always around the holidays, all local news stations warn users about that common scam and not to make those purchases, but of course it can happen other times as well and those same retailers still display them in the same way and wonder why the problem continues.

The retailer failed to protect your purchase and owe you the $40 for their inaction, but unfortunately they are not likely going to give it to you. The scammer was right in there store taking cards off of their rack and stealing the codes. They then put them back and wait for you to activate them.

An Apple Gift card can be “redeemed”

onto your Apple Account.

Once it’s been redeemed there, no one but you can access the value.

It’s not unlike depositing “extra” cash into a bank account for safekeeping.

How to redeem your Apple Gift Card, App Store Card, or App Store & iTunes Gift Card - Apple Support

If your gift card’s code was compromised, any value which the card contained could be used.

An activated gift card is just as vulnerable as cash to mis-appropriation.

One report I read mentioned you shouldn't even trust gift cards locked up behind the counter. There's no guarantee an employee won't take them home and do the same thing. A bit harder to get away with if the owner checks each morning for a card count vs. sales while s/he wasn't there. But still not completely safe.

I agree. As with any purchase it is a matter of reducing your risks. The public display of Gift Cards are more likely to be compromised than those secured by a retailer that is managed by their employees, but of course still possible. Even better is a purchase directly from Apple.com, but for those looking for a cash transaction, they must rely on a retailer.

AshleyMakely wrote:

What’s redeemed mean

"Redeemed" means, essentially, that you deposit the value of the gift card into your Apple Account.

Once you redeem a gift card, the gift card is worth nothing – and your Apple Account credit balance is worth more. Assuming that your Apple Account is secure, that means that nobody but you can then spend the funds (on Apple Store, iTunes Store, and App Store purchases).

Sad, but not surprising. They didn't secure the cards, but yet you're the one who loses out.