Airtel — bill plan issue

I have 2 airtel numbers [protected] and [protected]. The bill plan is
(1) 75 rs rental
(2) 500 local a2m mins free - pb
(3) 500 local and national sms free - pb
(4) free 2 gb offer data for 3 months
(5) surprise_eligibility_pack
(6) 0, 4g/3g data @ 3p/10kb_surprise provisioning.

According to this plan, our billl was coming fine around 300-350, but now our bil is coming in thousands. Few months back around in april, i got a message for surprize free internet pack for 3 months with 2 gb data. After that i did not activated any internet pack, but they kept on charging me without any intimation.in august when i got the bill in thousands i called them and filed a complained and messaged them for deactivating my internet pack (Which they had activated without my permission), but still my inernet is working and again i got the bill in thousands even after i am not using mobile net. I called the customer care, but even their managers are not handling my query. This is a clear technical fault from their side, but no one is listening.