All emails disappeared

We told Cox that we would like to discontinue service and gave a date two weeks away.  The next day all of the folders in my inbox were gone.  Fifteen years worth of information I'd been saving.  It was not junk, but rather emails that I kept filed in sub-folders.  I kept only items I wanted to keep and was constantly deleting unneeded items.  On-line chats, live calls to customer service and a visit to our local Cox center have not addressed this problem at all.  One agent suggested that the emails were deleted because there were too many, asking if I'd gotten a warning email notifying me about a pending purge.  I have had no communications like this at all.  A manager at the store suggested that I'd been hacked.  Weren't these emails stored on the server?  And isn't Cox the only one that could delete them all?  The only thing now in my PC's Outlook folder (.pst files) is the past two weeks.  I've been reading similar posts and am trying to understand imap, pop, outlook, and the other things that might relate to this problem.

Can someone help me figure out how to retrieve my emails?  The hardship and damage this has caused is huge.