Airtel Overcharging me for no fault of mine and refusing to REFUND the same_9880340848

Dear Sir,

I am writing to you after a lot of traumatic experience with Airtel and team for the last 3 months regarding my bill discrepancy. I am an Airtel customer for the last 15 years and I am just shocked that a simple issue has been dragged for so long without any solution. Recently on 21st December 2015 I change my Airtel bill plan from 799/- to 199/- and after discussing with the customer care over phone my plan was finalised. After finalisation I got an email and sms immediately regarding my current plan where no where it was mentioned that my 199/- data booster plan for 1 GB is valid only for 6 months. Even verbally when I spoke to the concerned it was never mentioned( you can check the call records on that date 21st December 2016). Suddenly from June 21st 2016 they have disconnected my 1 GB data plan without informing me( by sms, call, email nothing) and have been charging me per KB basis and my bill is coming very high. Every month I am having to make several calls to Airtel regarding this and they are agreeing for a waiver and after some days going back on the commitment and only give a part waiver. They agree for the waiver but it does not reflect on my invoice immediately and they go back on their commitments by another 15 days. Month on month they are over charging me and now blatantly are claiming that the data plan is not valid whereas "my account" on Airtel.in still says that I am on the 199/- plan for 1 GB. even when sms is sent to 121 for 'data plan' I get a reply saying ' X MB used out of 1024 MB( Attaching the proofs). They are failing to give me a solution and even if one senior officer commits to give a waiver the Appellate office has a different version. No body has a clue about what is the right immediate solution. Currently they agreed for a waiver of Rs. 1946/- and Rs.996/-( Rs. 2942/- total against reference number 71347773) and suddenly today appellate writes to me with a new version that only Rs. 2300/- total waiver will be given and I need to pay the balance immediately to enjoy continued service.

They clearly have a system error as it has been automatically entered as ' valid for 6 months" in the back end and they are unable to sort that system error. In return they are traumatising the customer. I will be continued to charge per KB basis for my data for the month of September and again this same issue will contine. Please suggest and help me out as I am frustrated being Airtel's customer.
Fleecing customer like is not right and as a consumer I can go to the court. Just because they want me to change from 199/- plan to the current 250/- tariff for 1 GB data they are doing all this as they think I am helpless.
Attaching proofs of screen shots where even an a Rs. 100/- discount for data for 12 months has been mentioned which has never been given.
Please suggest how I can escalate this to the Lok Adalat as I am not going to allow Airtel to cheat like this.

I also want to sue them for this mental trauma. Truly appreciate if you can help me out in this