I am unable to remove it and re add it due to another red error message at the top, stating, "MZFinance.FamilyNonHoH.CannotAddPayment."
1.
See -> Remove a payment method from your Apple ID
Remove a payment method from your Apple ID - Apple Support
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If you can't remove a payment method
If you have subscriptions like iCloud+, have an unpaid balance, or you use purchase sharing, you must keep at least one payment method on file.
2.
tried to do an in app purchase for a game with a gift card
See -> How to redeem your Apple Gift Card or App Store & iTunes gift card
How to redeem your Apple Gift Card or App Store & iTunes gift card – Apple Support (UK)
When redeeming a gift card, the amount will be credited to your (1) Apple Account balance and (2) you need to set your Apple Account balance as your default payment.
(1)
See -> Check your Apple Account balance
Check your Apple Account balance – Apple Support (UK)
(2)
See -> Add a payment method to your Apple ID
Add a payment method to your Apple ID – Apple Support (UK)
- If you want to change your card, you need to add first the new card, then remove the old card.
- or if you want to use your Apple Account balance, you need to set your Apple Account balance as your default payment.
See also -> What you can buy with your Apple Gift Card or Apple Account balance
What you can buy with your Apple Gift Card or Apple Account balance – Apple Support (UK)
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- You can't use your Apple Account balance to send gifts or gift cards.
- If you use Family Sharing, your family members can't spend your Apple Account balance. Funds that you add to your Apple Account balance are only available to you. Find out more about how purchases are billed to your Apple Account balance.
- Some purchases might require you to have a credit card on file, even if you use your Apple Account balance to make the purchase.
If you're still unable to update your payment method, Contact Apple Support.
if you still need help, get support from Apple directly -> Get Support or call Apple in your region see -> Contact Apple for support and service