Can't use Apple Account funds
I received a virtual gift card from Apple for a small amount.
I redeemed it, applying it to my Apple account. I can see that the balance is there.
I tried to purchase items in the Apple Store for less than that balance. I applied my funds. It showed nothing due on the purchase and a balance remaining on my account.
Address, phone number, email all consistent. Logged into the proper account.
Then when I click to finalize the purchase it says "Your payment authorization failed. Please verify your information and try again or try another payment method."
Checked everything. Of course I don't want to try another payment method.
I've tried removing the card then reapplying it. Paying a small portion of the cost on a real credit card. Nothing worked.
Spent 2 hours on the phone with half dozen departments through Apple Support. They couldn't make it work. Last theory one CSR offered was there was a problem with the gift card and they'd have to reissue (but the card redemption to my Apple Account was fine -- it was applying that account balance to the purchase that didn't work).
Looks like people here, on reddit and elsewhere have run into similar problems for several years.