Okay, it appears they offered a future credit, not a refund. I get why they may not accept that.
BUT - there is still something missing here. Hard to even call this a scam, unless the new person in the cabin did it. Nobody else would gain one cent from this happening. Nothing. Not a scam.
As to Carnival being at fault. Nope. If I post my bank account info online, the bank is not at fault. Right? Same thing here.
I am rather surprised that an email would not come from Carnival confirming the change in reservation status.
Why would someone do this?
Maybe someone dislikes her so much, they did it.
Maybe someone has nothing else to do and decided to mess with her.
Maybe someone wanted that cabin, and did it.
Maybe Carnival messed up and cancelled it - though they say they did not.
Again, there is more to this story that we are not hearing about.