Bought Apple Gift Cards and it says they are already redeemed

This link will take you to the section of the support article about what to do if your card has already been redeemed If you can't redeem your Apple Gift Card or App Store & iTunes Gift Card - Apple Support

I’d probably contact Apple to see if they can help determine if the gift card has really been redeemed, or if there’s something not working with the redemption.

If the gift card is already redeemed, it’s likely that a scammer someone unsealed the gift card before you bought it, affixed a label on it or something. There are a lot of gift card scams out there. If this does end up being the case, I’d certainly go back to the retailer where you purchased the gift cards.