Lesson ? I will complain to the police, contact me by post , all those who have lost money , I need all the evidence . Any person who lost money. YOU MUST GO SEE THE POLICE , justice will have work.
I'm really sorry that you've been scammed dude, and, you have the right to be upset / outraged etc, and, perhaps, on this occasion gathering people's statements and taking them to some form of legal authorities will be worthwhile, but, it almost certainly won't be.
May I suggest that you accept this, and move on?
I don't think whichever authority you could go to / I could go to would either care, want to, or, even be able to do anything.
This is the reality of playing with HYIP / Ponzi schemes, and, if you didn't realise that that is what this was, then I'm sorry about that too; remember if it seems to good to be true...
They all end, and, most of the time, there is only one real winner, and it's generally not the users, it's the admin.