Email from church domain being sent to spam for members using Comcast email

Many email messages from our church domain (valleycovenant.org) are being sent to spam for our members that have Comcast email addresses. I see this happening in my own Comcast email account and there seems to be no "training" effect from marking messages "Not Spam." I read in another thread that a Comcast rep helped someone with the same sort of problem, but I've yet to be able to get a Comcast person to respond helpfully to posts I've made on other threads. Private messaging these Comcast people on this forum seems to be very hit and miss. I also find that even though my email notification settings are all "on" for the forums here, I get no notifications when someone responds to a post here. AND I can't see any way to follow and easily return to threads which address issues I am concerned with. Overall, this forum seems like a pretty unhelpful place to seek help, unless one just happens to search and find a thread where one's issue has already been answered.