I unauthorised my account before returning a library book

Hi, I have been struggling setting up Adobe Digitial Editions to download books onto my Kobo. 

When I first created an Adobe ID, I didn't realise it hadn't set the password (as I followed through with Google account and it did it automatically). Then when I was trying to download a book, it said my username or password was incorrect (I now know this is due to a password not being set). 

As that was not working, I followed through with the second option - continue without the authorisation ID and the book downloaded. I then found out that logging in this way is not compatable to send to ereaders such as my Kobo and that you have to log in the other way. 

I then looked up how to un-authorise my account and then set it up properly - after creating a new password on the Adobe website. This then worked, however it would not let me download the book due to "E_LIC_ALREADY_FULFILLED_BY_ANOTHER_USER". 

I now realise this is because I did not return the book before I removed the anonymous account from the start. This also means I am unable to return the book at all, as it says I have to return the book using Adobe Digital Editions, but I previously logged out of this.

Please Help!!!!