Byjus — Cancellation of the course and refund

Address: Byju's, 6th Floor, Tower D, IBC Knowledge Park, 4/1, Bannerghatta Main Road Bangalore- 560029

I have enrolled for byjus ias premium course. They said that we are providing scholarship to you. With tablet learning program. But instead of tablet they provided me prerecorded lectures and optional subject lectures on my android itself. Right after 3 days I called them to cancel my course. But they said that we'll arrange a call for you within 24 hours. I call them many times. The reply was same. I do not understand the recorded lectures neither I can afford their EMI. It's been 15 days now I do not get even study materials yet.
How many times I have to call them instead of studying??
I just want them to refund.