Byju's — Cancellation of course

I have taken byju's IAS course on June 3rd. I was not sure about taking any course initially. But the byju's team convinced me to take the course. Later I realised that the product is not very helpful for me. So I have requested for the cancellation of product within 15 days trail period. The byju's team promised me that they will raise the issue and cancel the product. But after 15 days trail period they are not responding properly. Also the coordinator who enrolled me has been avoiding my calls and messages. Now it almost a month since I have purchased the product. We have been getting messages of EMI payment everyday.
Even they are calling my father about EMI payment. All I need is to cancel the product immediately. I don't even have hopes on getting the refund. I just need cancellation.