Byjus - No return and refund given to me even cancelled within 15 days of trail period

Recently on **th of August I purchased a course for my little brother who is in *th class , a counsellor visited our home and explained about the course and told us that if you don't like you can return the course in ** days from the day it arrives. I received the course on **th August and after using for few days my brother said he is not enjoying the studies so I decided to return the course as it was very expensive for us. So on *th of sept I mailed on their cancellation@byjus.com and support@byjus.com and requested them to return it and refund my amount. At first no call or mail response was provided so I mailed again to which a call was arranged and the mentor tried to convince me to take the course but I didn't accepted it. Few more mails were typed by me and few calls were arranged but no return was done. Now it's been ** days now and no response is given to me on this. On top of this my emi has also been deducted from my bank account. I feel cheated and helpless now as they don't response to any calls or mails and no one is there to complain as they work virtually.
Please help me here as again month will end and my emi will get deducted even we are not using the course.