Error returning book. Please authorise computer first

Only one of the books I borrowed from the Auckland Libraries ebook library is showing up on Adobe Digital Editions. I downloaded ADE and authorised my computer without an account and borrowed two ebooks. Then I erased the authorisation so that I could use my Adobe account, and authorised my computer under my Adobe account. Now it seems that no matter what I do or how I'm authorised (just with my computer, with my account or not at all), I cannot return these books and only one of them even shows up on ADE. According to a secondary application called "borrowbox" it is evident that I still have those two titles out on loan on ADE even if only one shows up there. I cannot return the titles using borrowbox either. I would just really like to return these titles. PLEASE can someone help me out.