Online threats and extortion demands

The short solution: don't respond anymore. Block the individual. That's the only trick to preventing sextortion or any kind of online extortion. Contact our law firm if you judge that this isn't enough.

This sounds like a scam. The threat and demands to extort money from you are obviously crime that needs to be lodged properly to the security agents to put a stop to it.
Have you given him any money or has he ever collected any money from you? Give us more information to enable us assist you.