This is my opnion because I don't know about the rule of law in usa, but a few years ago there was one project from usa that exit scam(TBIS or Titanium Blockchain) because there was a scuffle between their teams, investors were disappointed reporting the project to SEC and finally all the teams involved in the project go to jail, because Cargocoin is a usa project maybe you can report them to SEC because it seems the reason you are reporting is strong enough because the founder is only buying time to develop the project, but what I fear is Cargocoin project is a fictitious address and actually they are not related to usa. so I think this idea is a little iffy *cmiiw