Can't share my personal workspace with another user

Can't share my personal workspace with another user

I have a Pro subscription and have been very happy with it (as an ex-Evernote user, loving the simplicity and user-friendliness of Nimbus Note). However, a message flashed up a few weeks ago stating I'd been given access to the Business features from free. Well, I don't want them! Is there a way to turn them off?  

All I want to do is share a PERSONAL workspace with someone (another Pro user). I'm baffled as to how to share the workspace without filling in loads of "team" info - adding more complexity and confusion than is necessary. The other user has the same problem!

I wrote to Support (ticket 26298) asking how to downgrade back to "Pro" without the Business features - the reply was: 
"Hi You don't need to do Downgrade. After the end of the trial, the business organization is automatically deactivated.".

I didn't "opt-in" to a trial and it isn't useful to me (although am sure others may find it useful). 

Please can you let me know how to "end the trial"? Thank you!