Firstly do remove the phone number, this is a public forum and such information should not be posted directly.

Secondly, I think you have done what you can possibly do in such situations. Reporting to the local police is what you can do and beyond that is not in your control.

All I have to say is that when you are trading in amounts as big a half a lac, why not use an escrow? It is a simple measure and keeps you safe. Do remember that coins once sent are gone forever, they are no longer your coins. Hence in future do not make this mistake.