I've experienced exactly the same issue as DisgruntledTurtle. Have been a user since 2011 and use the regularly. In fact was at a conference taking notes just yesterday morning. Then, without warning, I'm logged out and had to do a password reset. When I log back in, there's nothing showing. Apparently, my last note was in 2017! Will be entering a support ticket myself but will be interested to hear if DisgruntledTurtle receives a response. Also, am curious to know if anyone else has experienced this problem.
I understand the need for apps to make money but burning / ransoming user data is a poor way to go about it.