Airtel — postpaid bill payment - fraud

An airtel sim sales person came to our house. He offered me to buy a post paid sim that will be giving me 32 gb data. I already own airtel pre and postpaid sims.
After getting this new sim activated, i got a message to pay the bill for the 2 gb data. So, i was being cheated that i will be getting 32 gb data while the data plan was only for 2 gb. I have never used the sim after knowing about the fraud. Now, i keep getting calls to pay the bills everyday. They simply keep adding everymonth bill amoount. Now it is 1200+. I have never used the sim and i have requested them to cancel the sim card many times. Still they keep calling me. I am very prompt at paying my other airtel bills.
Plz take action against them. They have started new way too exploit the consumer. They send a sales person home with the sim card with false plans and promises, then they start calling to pay bill for an unused sim card