Oh, ouch! Can't blame you for being irate.
If anything good can come from this, I've learned a lesson from your plight -- render image sequences.
Indeed. After Effects isn't nearly reliable enough to use anything but image sequences for a render that long.
When dealing with a large render like that, I'd also recommend rendering full res proxies of as many sub-comps as possible. (You can stack those before a full render of the comp in Render Queue) That way if you have issues or need to make changes, if the sub-comp isn't affected it will speed a re-render up dramatically. It's a nice insurance policy.