https://help.evernote.com/hc/requests/new - you get a boilerplate "have you tried this" response to try and take the pressure off the department; please reply to that to get more attention. It will still take a while. Another lengthy workaround is: if you have a Gmail account, there's a google add-in which does the same thing. If you don't have a Gmail account, Google will happily import your non-Gmail mail by IMAP from any another account and you can still use the add-in.
I've seen comments that Evernote gave up on the Outlook add-in, but I think that was the older versions. AFAIK Outlook 365 should still have that option available from the MS Store.