Carrier billing lets you buy apps, games, or services and charge the cost...

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 the cost directly to your mobile phone bill. If you have a monthly plan, the purchase adds to your regular bill. On pay-as-you-go plans, the amount is deducted from your available credit