When they shared the folder to you it sounds like you were actually asked to join their team - and you accepted. That isnt something easily done you are asked quite a few times if you want to do that (and it tries to force you to set up a second account for it).
The only thing you can do is ask the Business to restore your account and then REMOVE you from the company (not delete! remove!). You cannot do that yourself.
-
-
-
- 
Did this post help you? If so please mark it for some Kudos below.
Did this post fix your issue/answer your question? If so please press the 'Accept as Solution' button to help others find it.
Did this post not resolve your issue? If so please give us some more information so we can try and help - please remember we cannot see over your shoulder so be as descriptive as possible!