Indraprastha Gas Limited [IGL] — Charging extra amount in the name of security deposit every year without giving interest benefits to customer

I want to raise the complaint against IGL as they are looting customer in the name of security deposit every year if customer bill is above 1500 inr, although i have paid initial security of 6000 inr back in 2011 so ideally on compound bank interest the amount must be now above 12000 inr with them. And the catch is the unit consumption has not increased but the unit price has increased more than doubled(from 26 inr/unit to 55 inr/unit) but they have kept the logic of bill above 1500 which ideally should be increased as price of png has increased more than double. So this way they are looting 500 inr every year. I would request everyone to file complaint against IGL on https://consumerhelpline.gov.in to take some strict action against them. Please all the victim of IGL should complaint on this link and we may unite to do legal action because i know no individual will do case for 500 inr but 500 people can do case for these kind of scam against IGL. my yash.[protected]@gmail.com to connect