All Data from my Address Book and iCal have disappeared!

Since I activated iCloud, I've got annoying problems with some Groups items in my Address Book doubling up. I blamed a sync problem with iCloud so I decided to deactivate it. I have only one Apple device (a MacBook Pro), so in fact I don't need iCloud (I thought).

But... by doing so I lost ALL my data in the Address Book AND iCal. They are both as blank as a baby's bottom.

How to retrieve these data?

Annoyingly, the RESTORE function from Time Machine doesn't work either. "iCal and Address Book cannot be deleted or restored because they are part of XOS" reads the window popping up.

I'll give half my kingdom (if I had one) to the bright spark who can help me out.

A big thanks in any case,

Tony