Indiegogo won't do anything, because they can't.
No promises were made, backers have to accept that there are no guarantees and they are taking a risk.
And most of all, RCL have shipped units and delivered other perks (hall of fame).
So while RCL may have screwed up massively, that was always one of the options. IndieGogo are not going to get anywhere with debt collecters, because the bones that are left after the solicitors have picked out some of what they are owed, will be worthless.