Duped of 10 lakhs - 2 years ago

I am based out of Visakhapatnam , Andhra Pradesh. I came in touch with a person online and I have invested Rs Ten Lakh in a Investment Management Company of him called "Revtrade" based in Haldia (West Bengal). The company policy is to return 6-8% i.e 60000 to 80000 per month by investing in stock market irrespective of the performance. I later came to know that this is not even a company. This is not registered and this is plain fraud. I have never met them in person. I came to know of this person on Facebook and he has talked to him post that. I take the blame in believing and luring me into the deal. I have transferred the money via NEFT to the account and I also have an acknowledgment from them through email. Not only they stopped paying the returns every month. Now that I have asked my premium back - they are not returning it. It's been already more than 2 years 6 months now and still no response from him. I have NEFT details, whatsapp chat , emails confirming same How to proceed?