Hi gamecockks and welcome to Cruise Chat.
I'm afraid I agree with everyone else on this one. Thank goodness you and your party didn't suffer anything worse than you did from the horrible accident.
The first Customer Service person you spoke to should have told you that you won't get a future credit, instead of having you go through all that work. There is no doubt that any cruise line would have said the same thing. Had your travel agent or NCL (if you booked direct) offer you travel insurance and tell you why you should have it?
And although this is beside the point, could you really have guaranteed that you'd never, ever sail any other cruise line than NCL in the future, even if another line had better food, service, prices and itineraries?
I'm sorry you went through all that you did, and am happy that the accident wasn't more serious than it was.