Why can't I delete files from icloud drive?

So... for about 30 days now, I've had this problem - can't delete any files whatsoever on icloud drive. Note - always using the browser version - sign on at home (windows 7 pro), sign on at work (windows 7 pro) using IE or Chrome. Suddenly. today, after repeatedly trying to delete & getting the message "there was a problem... try later", I saw at the very bottom right of the screen, some letters in blue - 8 recently deleted items. I clicked on this link & a window popped up, showing 8 files with an option to cancel or delete all - I chose delete all. After this, I was able to delete all the files I had uploaded. Strange behavior of this application. Note - the spreadsheet in question is 5,846 KB in size - but that should not matter.

So, yesterday, it appeared that all the deletes worked - but today, they are all back again - I deleted them again, and for now, I'm not getting any message & they seem to be deleted.