This is the kind of situation where you think you're inside a movie like Matrix...
I had 3 calendars on Ical
They kept synchornizing bad, creating duplicates, errors, warning, all the Apple wichcraft that we all know
One day I decided to merge them all in one, and delete the others.
Alas, I was in such an anger that I deleted the wrong ones. And since then, they have disappeared for ever. Of course, in seconds, they vanished from all my iphones and ipads and other mac before I could shut them down.
After trying all the knows tricks (deleting the Ical files from library, calendars, and preferences, I decided to perform a full backup/REINSTALL from Time Machine.
A fresh one from few days before the disaster.
Believe it or now, but the dead calendars are still dead!!!
This is so illogical. A full resintall is what it is! THE SAME AS IT WAS BEFORE. But here, no!