Your story horrifies me and I'm certain you did anything wrong. How a cruise booking can just be cancelled without advice to the customer is beyond belief. In my case, I check the Personalizer every few days so if any of my cruises just disappeared I'd see it fairly quickly.
My minor, compared to yours, cancellation story is I recently had a shore excursion cancelled with no advice. When I just noticed I spoke to the Phillipines and although the staff there were friendly, the shore excursions are now full. I can accept things change but being told, I would expect should be routine.
Pleased you sorted out most of the mess and that too many years haven't been taken off your life. Not the lead in you want to a relaxing holiday.