Emails sent to customers with comcast.net email not appearing in Inbox or Spam

I work for a medium size business and we have important product emails that need to be reaching our customers during the coronavirus pandemic. We're having an issue that seems to be isolated to customers with comcast.net emails that I'm hoping I can get help with.

What we've seen is that even though our email tracking is saying that the emails were delivered, these customers don't report seeing the emails in their inbox or spam folders. This is a very trying time for our customers so any help here would be very much appreciated.