iTunes gift card already redeemed

Hello~ Click on below and work and review…

If you can't redeem your Apple Gift Card or App Store & iTunes Gift Card - Apple Support

Note you can click on other highlighted tabs of interest once inside the link above… including the one to contact Apple which is what you need to do in this case.

~Katana-San~

Bought it online from where, exactly?

If you didn’t buy it directly from Apple, there’s a good chance you got scammed. Contact whoever you bought it from.