Until then, on Evernote's Tos [1] scroll down to "What Else Do I Need to Know?" and read point f) of section "YOU EXPRESSLY UNDERSTAND AND AGREE That".
In summary, it says they are not in any way reaponsible for your data loss. Reading in-between the lines, it basically says, they will have outages, disruptions, or buggy updates and your responsibility is to defend yourself against these events.
[1]: https://evernote.com/legal/terms-of-service
I think you already assumed all these. I only elaborated on it because I saw this many times, even (especially?) with the largest providers like Gmail, AWS etc. And this will continue happening.
I understand (and a bit scared for) that most of the people don't even know how unsafe their data is, however, on HN I would expect everyone is (paranoid enough to) back up their data.
I hope you can recover your notes, and regardless of your success in doing so, please spend an afternoon looking up ToS's of the services you use.
(disclaimer: I worked a bit in the backup sw industry, and yes I have multiple full offline copies of my emails and notes for the past 20+y)