Carrier billing lets you buy apps, games, or services and charge them directly...

https://xeon-wiki.win/index.php/What_Should_I_Do_If_I_Do_Not_Recognize_a_Carrier_Billing_Charge%3F

Carrier billing lets you buy apps, games, or services and charge them directly to your phone bill. If you have a monthly plan, the cost appears on your next bill. For pay-as-you-go users, the amount is taken from your available credit