Pay-by-phone lets you buy digital goods and services with just your mobile...

https://fair-wiki.win/index.php/Why_Gaming_Sites_Favor_Pay_by_Phone_Deposits

Pay-by-phone lets you buy digital goods and services with just your mobile device. Charges go straight to your monthly phone bill or use prepaid credit if you have it. It’s a simple way to pay without needing a credit card or bank details during checkout.