Byju's — Cancellation of subscription

I have mail byju's for cancellation of my course because I am unable to understand the study.Many mentors have called me and told me that there will be a call from the cancellation team within 24 hours.but no one called me.
When I try to contact them but got no response.I am trying to cancel my subscription since 16th of march but there's no cancellation yet please help me to cancel my subscription.