TRAI has manadated all Telecom operators to provide the details of the costs each time a user is charged for voice or data on the Mobile. All the operators will have to send an SMS to the users immediately after the Subscriber is charged. Â This rule by the Telecom Regulatory Authority of India would be applicable for Prepaid Subscribers only.
The data provided must include following
Duration of Calls or quantity of Data Used
 Cost incurred
Remaining Balance
Additionally any Subscriber can get Item wise details of the calls and data in a specific period  within 30 days of making the request and paying not more than Rs 50.