Based on my extensive experience of being disappointed by QB, that's kind of what I figured, and since we went from the obsolete v21 straight to v24 (remind me never to go to the current version again) over a month ago, a) we can't go back to a v21 backup (I presume), and b) even if we could, we'd have over a month's worth of data entry to put back in.

This is why it's imperative that you resolve this immediately, QB team.  It's so maddening how you manage your product.