Well, I have to say this is the most bizarre story I've heard in quite some time. Unfortunately, there is not much anyone here is going to be able to do for you.
You have to follow up this episode with Carnival's head office in Miami. I'm sure they will investigate it thouroughly. Reading your "side of the story" it would seem wise to have an attorney represent you to be certain the entire story is brought to light!
You don't mention which ship this incident occurred on, but I assume that Camp Carnival is run pretty much the same on all their ships. I can't understand why this time the Camp Carnival experience would have been any different than on your previous cruises.
We'd certainly like to be kept advised as to how this develops.
I don't really want to start a flame war but I believe this displays how cruising with a toddler can present problems for the family cruise experience. I don't know what the "magic age" is for making it a great experience, rather than a bad one. But I think there is most definately an age that's too young to cruise.
And I think that it's dangerous for parents going on any of the cruise lines to expect the "kids programs" to accept the responsibility of entertaining the kids for full days.
I've been cruising with my kids since they were 8 and 13, and I've yet to encounter a situation even remotely close to this type of incident.