Zebpay - Fees charged for almost 3 years without any intimation or invoice

I had created an account with Zebpay almost *-* years back and I had bought some crypto with them. They had charged certain for the transactions and it was fine. But one fine day they decided to charge fee for every month in which there was no transaction!! Basically they wanted people to trade more than grocery shopping! This was almost * years back. There was no consent taken from users like me and they started charging me this. And every month they had been charging me this fee of almost close to Rs. ***-*** for almost around * years now! And they never sent me an invoice for all the fees they have collected! Basically I had no way of knowing that they are charging this exorbitant fees. Despite reaching out to them multiple times, they are now saying they will take this as a “feedback” but they can’t refund my money!