Reliance Communications — shutting down the services without refunding the advance rental & security deposit

Reliance communications in the month of jul 2017 sent me a bill of rs. 749.24/- + taxes to me against my monthly rental of rs. 349+taxes for my postpaid connection. When i lodged a complain for the same then i got a call from customer care, kolkata that they have upgraded my plan and the bill is two months advance rental. When i asked how they have upgraded my plan without my wish/request they informed that it was done for all the customers. After that i said i don't want new plan as my old plan was enough for me and i don't want to pay additional rs. 50+taxes for new plan rental to which they said that my rental will remain same and they will give rs. 50/- waiver in every bill. They also told in my new plan i'll be upgraded from 750 minutes of calling to unlimited calling and from 500 mb data to 6gb data per month. After which i agreed as my rental was not increasing. Then i paid the full bill including advance rental. But next month they gave only 1gb free data against promised 6gb. I tried contacted their customer care but there was no response and my call was never connected to customer care executive. I even mailed then twice on 21 sep 2017 & 25 sep 2017 but got no reply. Now they are shutting down their services and asking the customers to port to any other network. My grievance is that reliance communications is not contactable through any means. My advance rental and my security deposit which i've paid at the time of connection is pending with them. Kindly help me in recovering my amount and i also want to lodge a complain against then as how without making a single call to existing post paid customers they are shutting down their services and why they have collected advance rental in jul if they were planning to shut down their services in nov or dec 2017. It is a fraud done by them through which they have cheated many customers like me.