First, call on the call centre number of your operator (for airtel 198, vodafone 111, etc).
If ur problem is not solved, then ask them to give the email id of the nodal officer or u can obtain it from this
link.
If the nodal officer is not able to solve ur problem, email to their appellate (can be obtained from the same list).
Even if the appellate is not able to solve it, don't hesitate to lodge the complaint
here. This is the official grievance portal of India for all the Ministries and Departments. (Here the Department would be Department of Telecommunications.)
Remember to save the acknowledgment no. that u receive from the Call Centre, Nodal, the Appellate and the Complaint No. from the Grievance Portal.
After lodging the complaint at the official portal, within 24hours the representative of Airtel called me and solved it to a certain extent.
Even the officer of the Grievance Department from Delhi called me to ask if the problem was solved or not.
If ur problem still remains unsolved, go to the Consumer Court. You donot require any lawyer for it.