Hi.
If you have an unpaid balance
If you see a message that says 'billing problem with a previous purchase' or 'verification required,' you have an unpaid balance. Apple couldn't charge your payment method for a previous purchase. Until you pay your balance, you might be unable to:
* Make new purchases
* Download free apps
* Use subscriptions
After you pay your outstanding balance, you can make new purchases or use subscriptions again.
Pay an unpaid balance
You can pay an unpaid balance by retrying your purchase, or by using a new, valid payment method. You can also purchase and redeem an Apple Gift Card or App Store Card.
If a message says 'billing problem with previous purchase' or 'verification required' - Apple Support
Go to App Store → your profile in the top-right corner → Purchase History, and check for any unpaid items. If there are any, add a new payment method instead of using your existing one and see if the payment goes through.
If the problem persists, contact Official Apple Support
MindBlown.