I need help in paying old subscription without having debit card saying error.

Hi i followed all these steps.

Use an Apple Gift Card or App Store & iTunes gift card to pay an unpaid balance

1. Purchase an Apple Gift Card or App Store & iTunes gift card.*
2. Redeem the gift card.
3. On your iPhone or iPad, open the Settings app, then tap your name.
4. Tap Media & Purchases.
5. Tap View Account.
6. Tap Purchase History.
7. Tap the order with red text that says Amount You Owe.
8. Tap Pay with Apple ID Credit.

After you pay for the unpaid order, you can make purchases with your remaining Apple Account balance.

and i am still unable to pay the past due subscriptions and i need to pay for 2 apps so phone can let me download apps without saying error on my payment info i deleted it and calls customer service to apple and my bank and still have not found any solution.