While I can't and won't debate the rude and uncaring attitude part of your post, I will say that if you read your contract, that is what it says. No refunds that late in the cruise.
I assume you did not purchase trip insurance. This is a good example as to why you should have. I imagine they get a 100 calls a day from people wanting to back out of their cruise or some form a credit because they had a last minute problem and couldn't go on the cruise.
Except for the "rudeness" side of this, you could have expected the same response from any other cruiseline- the contract says "no refunds" after a given date. So their resolution is probably no different than any other cruise line would have given you.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise, Magic 1/14
NCL Dream October 2006, RCCL Mariner OTS June 2007, Celebrity Silhouette 2013