'Someone has already set up Teams for your organisation'

Hello, 

I have an Office 365 for Apple 'Personal' account. When I was invited to use MS Teams for the first time a few weeks ago, I think I incorrectly setup my account because now this window pops up;

My Office 365 subscription is linked to the second, 'Personal' account listed. I would like to delete the 'Work or school' account, which I created in error.

Regardless of which account I sign into, I get the following error message;

'

Even though I've only got one email address, if I click 'Use different email address' it directs me to login.microsoftonline.com which I can login into my 'Personal account' with.

BUT, if I then want to log into MS Teams, I get the following error;

As far as I'm aware, I am the Admin but I can't figure out how to enable Microsoft Teams.

Ideally, I just want to delete the 'Work or school account' and have my Teams account with my 'Personal account'.

I've been trying to resolve this for many weeks and multiple phone calls and online chats with Microsoft. Am very ready to have it sorted.