Re: Redeemed Apple gift card lost
You might want to check if the redeemed gift card is now a $25 Gift Card balance, or, a$25 Apple Account balance ? See how to: Check your gift card balance - Apple Support
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Else see what to do:
If you can't redeem your Apple Gift Card or App Store & iTunes Gift Card - Apple Support
Eg: says:
"Card has already been redeemed
If you see a message that says that your card has already been redeemed, you might have already redeemed it. Sign out of the App Store or iTunes Store on all of your devices, then sign back in. This refreshes your Apple Account balance.
Learn how to check your Apple Account balance.
If you need more help, contact Apple Support."