Carrier billing lets you buy digital products or services and pay using your...

https://www.thecoastlandtimes.com/sponsored-content/pay-by-phone-how-carrier-billing-quietly-became-an-everyday-payment-method-4a6c068e/

Carrier billing lets you buy digital products or services and pay using your phone account. Instead of a credit card, charges appear on your monthly phone bill or come out of your pay-as-you-go balance