Touch Missing book

A book I am reading -- Full Circle, by Ellen MacArthur -- suddenly refused to open, and there was an error message saying the file may be corrupted.

I deleted the book and connected to Kobo Desktop to reload it. It was on Desktop, which synced annotations with my KT but said all my books were on my reader. Not so.

I then connected to my Kobo account through my browser, went to my library, and found that the book was not listed there. I searched for it, and when I selected it I was told that it was already in my library. I clicked on the button below the cover picture on the search results page, and when I then went to my library the book was now there.

I re-connected my KT by WiFi and pressed the sync button, but when sync was completed the missing book was still missing.

I then started Desktop again, and now the book was missing from there also and was not downloaded when Desktop synced.

I went back to my Kobo account through the browser, and found that the book had again disappeared from my library.

I am using ver 2.1.1 which I manually installed some weeks ago. I have bought and downloaded and read several books since then without problem, so feel there must be some other problem. (Even if there were a problem on the reader, the book should still download to the Desktop, right?)

Any suggestions or help would be appreciated.

Tom K.