Email Settings on My Galaxy S5

When I delete the emails on my Cox account from my phone they come back as soon as my email updates again. I am using Imap.cox.net port 993 with SSL as my incomming settings and smtp.cox.net port 587 with TLS as my outgoing setting. I thought this was an issue with my phone but I tried the same settings in my Iphone 4 and had the same outcome. What am I doing wrong? Thanks for the help in advance.