First of all you should have realised that nobody can be able to pay interest on the money invested with him @ 3% per month.
If somebody is paying that huge interest amount then his business should be doing very well and it should be a big establishment.
Whereas from your contents it appears that the person who is doing business is not into a very big business neither he is getting anything to the extent of paying back to his investors as return of investment.
This is a clear case of fraud.
You have been trapped into this racket by fraudster making you believe in him without giving room to you to suspect his integrity.
The initial return of interest amount for few months was to instill confidence in you so that you will be prompted to invest more and more, to enable him to get away with huge amount.
He might have cheated many people like you, you can probe into this and collect the details of the person who too were being cheated by him, and give a complaint along with others to the economic offences wing of district police to take proper legal action and for recovery of your Mooney.
Besides you can issue a legal notice to him and file a money recovery suit simultaneously, if possible you can file a petition seeking to attach his property before judgment for the security purpose in the money suit,.