It seems that the same ISBN number has been issued to two different books, so there is no "correct book" The only way to get around this is to add your book without the ISBN (please leave a note about that). When you were adding the book, did you not see a message "This book is already in the Library. Click Save to add it to your Bookshelf." I just tested it and that message appeared. It can take a few minutes for deleted books to be completely removed from your Bookshelf so you don;t need to keep deleting it. Just leave it for an hour or two then check again - I checked and it is gone.