Issue: Can't browse user's files

[JJ3000]

I downloaded quite a few files from one particular user, and now I cannot browse his files anymore.  He has not changed anything on his end but it always refuses to show the files.  I can search and randomly find his shared files and download successfully there.  

Is there some bug where if you download too many files from a user, it stops showing his files altogether?  Is this something that can be fixed?  This is kinda frustrating.  

[Martin D]

A user can block another user. But sometimes the user is no longer serving (either a schedule, or the associated file drive is offline). You can message the user?