Byjus - Money not refunded even after requesting to cancel the subscription multiple times

The byjus councellor wanted to me to buy byjus subscription so he convinced my parents by buttering them. He said that before ** days you can cancel the subscription and they will refund the full amount we payed in advance but if we cancel after ** days they will refund half of the amount payed. I agreed to them and when the product came the memory card didn't contain any recorded classes and after few days the tab was not working properly but when I contacted them they would ignore my call or they would say that they will call after few minutes and then they would never call. I contacted them multiple times but they didn't follow their rules of refunding .they cut **** ₹ every month they nearly cut *****₹ so far .so now I want my money back