Hello Mombo,
It would all depend on the settings on each individual device. If you are deleting emails on a device that is set up as POP3, it will delete the email off of the device but not the server. So when you look on a device that is set up as IMAP or the webmail website you will still see the email. This can make it look like the emails are reappearing over and over.
This appears as if you may need someone to look into your account. We would definitely be able to assist you with this. Please reach us on Twitter at @CoxHelp, visit us on Facebook, or email us at cox.help@cox.com. Please not personally. Provide us the name on the account with the complete service address with a link to this thread so we can get started.
Crystal S.
Cox Support Forum Moderator