Star Health And Allied Insurance — Not replying after purchase of policy

I had purchased star health family optima plan in the month of november but in between the process after medical diagnosis, I disapproved policy and sent mail to starhealth to discontinue it but now they are not entertaining my calls and not even replying to me.
Person who was looking after my policy and used to call me many times a day, now not responding to it.
This seems like fraudulent activity on their side.