Pay-by-phone lets you buy digital products or services by charging the cost...

https://wiki-square.win/index.php/Do_Pay-By-Phone_Transactions_Work_Without_Mobile_Signal%3F

Pay-by-phone lets you buy digital products or services by charging the cost directly to your monthly phone bill or prepaid credit. It’s a simple way to pay without entering card details, making checkout faster and easier on your mobile device