Byjus Company - Byjus not refunding my money

I have been a victim of the byjus online class scam. Off lately they started calling me on and off to join their online classes and I kept saying no to it, these calls were so frequent and so many that even at night they were calling, the associate kept telling me I can opt out of it if I don't like the course within ** days of the study material received. They made it so difficult for.me that I finally that I'll give it a try, again they ensured that the money is refundable if I don't like the course.
The course was ordered on *nd Sept and the byjus learning material and SD card was delivered to me on **.**.****
On **.**.**** I fwd mail requesting for cancellation however I haven't received any update on cancelation.
I keep requesting for the cancelation by calling them.on their numbers provided and they keep promising a call back but no body calls back..
The initially received * or * calls from the cancelation department and they said I the course cannot be canceled.
The course was offered at a cost of ***** out of which the first installment had already gone for the sum of *****.** on the *th of October ****.
This event has caused so much of trauma to me that I don't know what to do, they are forcing me to make the entire payment by telling me that the course cannot be canceled. This is and educational firm that cheats the parents. I don't want any other parents to go through this kind of trauma.i request proper action to be taken against this firm.