I had to just go and set up rules for common spam in cox web mail and set up allow rules for good email, and keep a good eye on my spam folder for legit emails there, because no matter how many times I tried to tell Cox it was LEGIT email - for example, one email would come from support@ and the next one would come from contact@ THE SAME DOMAIN, one would be marked as spam, the other wouldn't be!! - they completely refuse to be sympathetic to users' needs and actually address the known issue they continue to have. I called Cox at LEAST 8 times over the course of a few weeks about this idiotic behavior of their spam filtering, argued with them, pleaded with them, and it's like talking to a brick wall.
DO NOT USE COX SPAM FILTERS THEY ARE BUGGY AND YOU WILL LOSE IMPORTANT EMAIL BECAUSE THEY REFUSE TO DO ANYTHING TO FIX THE PROBLEM. You will have to set "Allow" rules for real email and "Delete" rules for spam and watch your spam folder, because it doesn't matter how much you talk to them or how many emails you send to thisisnotspam@, they will KEEP RIGHT ON DELETING YOUR IMPORTANT, LEGITIMATE EMAIL.
This is pathetic. FREE email services like Yahoo have FAR FAR superior spam filtering than Cox, and you actually PAY THEM and decent email is supposed to be part of your paid service! The so-called engineers responsible for spam filtering with Cox NEED TO BE FIRED. There is absolutely NO explanation that is good enough for Cox's atrociously bad handing of spam (or non-spam as the case may be).
And PLEASE moderators, don't bother trying to come and explain the whys and excuses you've used on people over and over about how spam filters work, because no excuses really work when this has been going on for YEARS!! Two legitimate emails...same domain...different email addys, one marked spam, the other not marked as spam. Can't tell you how many times this was done before I just went and set up my own rules for email. You have a HUGE problem and you need to fire the people responsible for it and hire a new team that does know how to handle it, and you need to spend some of those millions you're making from grossly-overpriced Cable TV and get a better relationship with the major spam filtering agencies, because the ones you're using now are doing a deplorable job.