Was the document saved locally on the computer's hard disc or was it saved only in the cloud?
Generally, I don't like saving documents I'm actively creating and editing as cloud-based documents. If the Internet connection goes on the blink even just for a second it can do bad things if the computer is in the document saving process. I'd rather save locally and then upload a copy to the cloud later.
Astute Graphics' Autosavior plugin is pretty good. You can get the plugin for free and keep it just for signing up for a trial of their plugins. Autosavior boasts additional controls over stock Illustrator features, such as being able to save copies in more than one location.