follow this guide: https://www.xfinity.com/support/articles/spam-filters-and-email-blocking-new-experience
Under settings in "Filter Rules" check for any email filters. Also check "Auto Forward" for any email forwarding. If you haven't changed your password recently, i highly recommend doing so and enabling two-factor authentication. Also review your Security Questions and your third party recovery options if they have not been updated/secured recently.