Can I get a refund for already redeemed Apple Gift Card?

click here ➜  contact Apple Support.

If cash refunds are required by law

You can’t redeem or return Apple Gift Cards, App Store Gift Cards, or unused Apple Account balance for cash, except as required by law. If your jurisdiction allows for refund of redeemed gift balances, you can contact Apple Support to request a refund. When you contact Apple, include the following information:

• The primary email address that you use to sign in to your Apple Account
• The refund amount
• Your current shipping address

Also for your protection, never purchase Gift Cards from a retailer where they are displayed on a rack that is open to the public to tamper with them. In that case it is the retailer that has failed to protect your purchase and you were scammed right in that store. Ironically some of these same retailers lock up products that are easily stolen from them, but don't have the same concern when the money is stolen from their customers.