If you do ever end up in that situation again, (or someone else is,) you can download the notebook by moving it into a folder in OneDrive. Then go to the web and use the option to download the folder. That will zip up the folder, with the real one drive files inside.
You'll still need to find an app to import them into your new note taker though.
Which is meant to be the same as a rejection. If they have correctly implemented it is another thing.