It appears that Idea Cellular has started carrier billing for Windows Phone App Store, allowing users of Windows Phone on Idea Cellular's network to pay for digital content likes apps and games with their phone balance. Several users on the Windows Central Forum have confirmed the availability of the said feature. It looks like Idea Cellular is the only carrier which is supporting carrier billing for Windows Phone devices. It should also be noted that users can't refund any purchases made through this billing mode.
Microsoft is working hard to improve their platform and increase the users by inviting more smartphone brands to make Windows Phone devices. Have you used this feature? How was the experience? Let us know your thoughts and experiences through the comments section below.