Byju s - Byju not received the services and not responding for refund

I did registration of my son Snehit Gaikwad with Byju in last month on **th oct. It's been over one month now but still we haven't received any learning device or learning documents. During registration we been told that we will receive everything within ** working days on my London address but nothing worked like that. Since couple of weeks i am chasing with Byju sales team, Grievance team, support team, cancellation team over the email but no one is responding to cancellation and refund request. I am reachable on +************ for direct call and on +************ for WhatsApp call.