All of my new Apple Gift Cards show no remaining balance

Where do you bought the  apple gift cards?

If you can't redeem the Apple Gift Card or App Store & iTunes Gift Card, you must contact the 'store' where you bought the Apple Gift Card or App Store & iTunes Gift Card, and file your complaint with them and request a refund. You have proof of payment right?

If necessary, report to the police if you think you have been scammed.

Your case has nothing to do with Apple.

See this Apple article:  If you can't redeem your Apple Gift Card or App Store & iTunes Gift Card

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

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Card is not valid

If you see a message that says that your card is not valid, here's what to do:

1. Make sure that your card is not an Apple Store Gift Card. Apple Store Gift Cards are gray, white, silver, or gold. You can’t redeem Apple Store Gift Cards in the App Store or iTunes Store. Find out what to do if you have an Apple Store Gift Card or don't know what type of gift card you have.
2. Try entering your redemption code manually. When you redeem a gift card, tap or click "You can also enter your code manually." Make sure that you enter the redemption code that begins with "X", not a different number on the card.
3. Make sure that you enter the correct characters. Some letters and numbers look alike, such as:

• B and 8
• D and O
• E and 3
• G and 6
• O and Q
• O and 0
• S and 5
• U and V
• Z and 2

Beware of -> About Gift Card Scams -> About Gift Card Scams - Official Apple Support 

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Where to buy a physical Apple Gift Card or App Store & iTunes gift card? 👉 at an Apple Store or an Apple Authorized Reseller in your regio.

If you have a valid payment method on file, instead of buying or order an App Store & iTunes gift card, you can Add money to your Apple Account balance anytime, no gift card needed, see -> Apple Gift Card - Apple (UK)

Hi there,

Follow the instructions here: If you can't redeem your Apple Gift Card or App Store & iTunes Gift Card - Apple Support