Consumer Redressal

I had subscribed to airtel 4G WIFI 10GB data plan at 999 plus taxes in November 2013. My connection no is 8585831324. Data usage beyond 10GB was free. Every month bill of 1122 was generated which I have been paying. In January 2015 , bill of 1679 was generated, for which I raised a complaint vide SR no 60066600 on January 29, 2015. Enhanced bill was again generated for February 2015 and I again raised a complaint on march 8, 2015 vide SR no 60668643. Airtel have not responded on any of the said complaint. Finally again on March 15, 2015 I wrote them an email in response to their payment reminder asking for clarification and rectification of bill. They have responded that there has been a change in tariff plan. Airtel should have intimated me and given me an opportunity to decide whether I want to continue with their services at revised tariff. They cannot sou moto change tariff and ask customer to pay exorbitant charges.