Vodafone India — Overcharging by vodafone

Address:

Mumbai City, Maharashtra, 400013

All of a sudden spike in my april 2016 bill from vodafone.
I usually billed averagely around rs 1000. And now all of a sudden its doubled.
I saw the detailed bill and the internet usage just shows absurd figures.Infact i switch to wifi when i am at home and downloading something, then how can the internet data usage sky rocket with the wi-fi on?
I have been writing to vodafone since last 10 days but havent got an solution as yet. They simply keep forwarding generic replies. Vodafone needs to clear this unexplainable figure from my bill.
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