That guys is beggar. How come he blackmail a project for a merely 300$ thats so cheap and to ruin a project by doing that is not a good way to extort. If that someone have proof and evidence to completely destroy the project then so be it but asking for money is some how a noob move in cryypto. Im sure those people are laughing now about the blackmail.
If that unidapp tried to run, then they will become scam but of course projects like that with no concrete info is really suspicious.