I do have another account that hasn't been used for 6+ years. I have checked that too and that one hasn't been erroneously upgraded either.
I guess the forum says "Basic" because the subscription hasn't been renewed.
If I try contacting Evernote it asked me how I paid, when I select 'iTunes' it tells me I have to contact Apple. When I contact Apple, they say it's nothing to do with them and to contact Evernote - stalemate.
I have emailed Evernote but not yet had a reply......
Helpfully the auto response says 'If you need help right away, contact us via live chat (Evernote Premium & Business).' - Stalemate again.