Adobe digital edition. says sent ebook (bought at waterstones online) to my Kobo Glo but it isn't there. Tried again, ADE says already on device but it is not on kobo or in kobo desktop library. what to do? i have no problem downloading ebooks from

Why is ADE saying downloaded ebook (bought from Waterstones) to my Kobo Glo but it isn't there!  I tried doing it again but ADE says it is already on my device- it isn't.  What should I try next?  The ebook is not visible in my Kobo PC  desktop library but it is available on my PC through ADE but I am going away & cant read the book on the PC even if I wanted to. I have tried syncing to no avail.