Idea Cellular — Activated charging vat without prior consent

Address:

530016

In my case i ported from idea to airtel. The bill period ends on march 27th in idea and it's 716/- but i paid 750/- and ported to airtel. My airtel connection activated on april 9th. I. E 13 days usage of ideas network utilised by me. For this 13 days i got a bill of 3106/-for this short period. Now my question is how can they make such over rated bill. Previously i was in 525/- plan in idea since some years and i argued that they should charge me as per that plan only and proportional to 13 days. But they said “once you are out on port you are not eligible for any plan”. That is fine but they should have asked me about my consent/ plan option etc. And how can you say that i am out with port when still i am using idea till the other network gets activated. And how can you bill as per your own wish with out my consent/ authorisation. Please tell me how to go about this. Idea company personnel met me personally and told me that i should pay the bills or else my number will be blocked. Please help me out.
Trai says vas tariff can't be changed with out consent of consumer.