I am having the opposite problem from most. Email I get from a bitx20@groups.io discussion group keeps getting marked as spam when it is *not* spam. I have had my account turned off twice in the past month due to receipt of emails from this discussion group about a new amateur radio product that is seeing amazing popularity.
I have sent three emails to ThisIsNotSpam@cox.net asking that the filters be tuned to allow groups.io discussion group emails to be allowed through as regular email and I have not heard a single reply from cox on any of my requests. Not one. I just sent another one this morning, 2/7/2018.
This is absolutely ridiculous! If I heard back on any of my previous emails, even just saying support acknowledges receipt of my emails, it wouldn't be so bad. But it's just like my communications are going into a black hole at cox!