I don't mean to downplay this but seriously, make backups of all data that is important to you. Lots of things can go wrong everywhere and they do go wrong. Maybe it is a sucky app or maybe your own error -- if you have a backup, you don't need to worry.
I know this is no excuse for Evernote's app being at fault, but if something matters this much to you, you should not be trusting anyone or anything and the only way to stay safe is to have backups in multiple places. Might seem like a PITA but it is worth the effort.
Not being an Evernote user, I'm not sure about this, but-- it sounds like the author recorded the corrupted file using Evernote (...sometimes instinct steers me toward the green elephant’s "record" button and I play for a while.).
A backup of a corrupt file wouldn't solve the problem.
I know this is no excuse for Evernote's app being at fault, but if something matters this much to you, you should not be trusting anyone or anything and the only way to stay safe is to have backups in multiple places. Might seem like a PITA but it is worth the effort.