Pay-by-phone lets you buy digital items quickly by charging purchases directly...

https://andersonsimpressivecolumn.urbanvellum.com/posts/what-is-direct-carrier-billing-dcb-in-plain-english

Pay-by-phone lets you buy digital items quickly by charging purchases directly to your mobile phone. Whether you have a monthly plan or prepaid credit, the cost appears on your bill or deducts from your balance