Airtel
Money charged even after disconnection

I had applied for fixed line telephone which later on i requested Airtel to disconnect it. Which eventually they did it. I received confirmation for disconnection. Inspite of all these confirmation they are sending bills for payment for last three months and when their executives called up for reason of disconnection and my explanation to them. They have not refunded me my money over and above. They are sending bills for payment followed by harassment calls.