On @comcast.net Junk - Block Sender is not working

Thank you for reaching out to us here @sgtjdc. You can set up a spam filter for those emails.

1.  
2. Open Xfinity Email.
3. Click the Gear icon  on the top-right of the navigation bar, then click Email Settings.
4. From the menu on the left, click on Advanced Settings.
5. Click the Automatically move spam and potentially harmful messages to the Spam folder option. Enabling Spam filtering will move emails designated as spam to the Spam folder and delete them automatically after seven days.