Carrier billing lets you pay for apps, games, or digital content by adding the...

https://cashsexcellentblogs.rivetgarden.com/posts/why-did-my-carrier-billing-payment-get-declined

Carrier billing lets you pay for apps, games, or digital content by adding the cost to your monthly phone bill or subtracting it from your prepaid credit. It’s a simple way to buy without needing a credit card or separate payment app