Issue Returning 4k Cable Converter Wifi

I've been getting emails to return my 4k Cable Converter Wifi but I have already shipped back all my xfinity equipment over a month ago...I even have the tracking confirmation that it has arrived. I also can't figure out how to direct message on this forum. It looks as if I only have the notification bell in the top right corner next to my user profile so I cannot find a direct message button.