Apple ID balance refund

See -> Check your Apple Account balance -> Check your Apple Account balance – Apple Support (UK)

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If you have an Apple Account balance that you can’t use

You can't redeem or return Apple Gift Cards, App Store & iTunes Gift Cards or unused Apple ID balance for cash, except as required by law. If your jurisdiction allows the refund of redeemed gift balances, 👉 you can contact Apple Support to request a refund. 

When you contact Apple, include the following information:

•               Your Apple ID.

•               The refund amount.

•               Your current delivery address.