Probably a good place to start since Indiegogo ignores complaints. And if local authorities can't help, they probably know where to escalate.

And since Indiegogo is in the US, a complaint to the Federal Trade Commission (ftc.gov) might help, as would the California Attorney General (where IGG is based). I know the California AG has been after IGG for pretending to be a mere innocent intermediary between customers and project owners, so additional anecdotes my help their case.