Airtel forcing me to pay for unused not activated service

Hi,

I had taken international roaming pack from airtel for 10 days. This cost around 2999 + tax. However, they have Auto renewed the same and charged me double.
I have used the service for the first 10 days and have called Airtel customer care to disable the service. Customer Care executive clearly told me I will not be charged for the next ten days. Please check voice log.
When I got the bill i was charged double. I mentioned I’m not willing to pay for a service I have not used. They threatened me if I don’t pay they will terminate the service. I have been there customer for 15 years. They say their systems autorenewed the policy? Why, I asked for ten days only. Also called and confirmed.
My phone number: 9845225527
Complaint numbers:76525975
Complaint number: 2453834192

I had also called on may 22nd 2017. However, they don’t seem to have a record.

Please suggest, this is at level of bullying.

Regards,
Jasleen