I need to schedule a technician appointment

I have had multiple TVs in the house come up with the error code RDK-03003 over the last week, this has also coincided with using a new updated TV set box, even though it definitely appears to be used and not one that is brand new. I've restarted everything at least a couple dozen times, I've replaced all cables, I've plugged HDMI cables into multiple ports, I've gone through the Xfinity assistant countless times, there are no other options left for me except to have a technician come out and look at things.