Blocked incoming e-mail from my other outside account to my cox e-mail.

For over a year I have been able to send e-mails from my e-mail account other than Cox to my Cox e-mail account.  Last week my e-mails from that account started to be blocked by Cox.  I have spent over 4 hours on the phone with Cox techs who confirmed from the error codes provided by the other e-mail provider that they meant Cox felt it was spam and they were blocking it.  It was e-mails from me to me with vacation pictures.  I explained that to each of the 7 techs and all each tech did was hand me off to another tech.  It was a very frustrating experience.  Has anyone every encountered this problem with the new Cox e-mail system?  Does anyone have a solution.  I am going to start calling again this week to try to get Cox to unblock my e-mails from me to me.  This is not great customer service.