Issues Upgrading to X1 TV Box

I'm having issues trying to upgrade my outdated TV equipment to X1 TV boxes.

I have two TVs - the cable for the main TV in the living room does not work, but the cable for the TV in my bedroom does. I figured that the living room wasn't working because the equipment is so outdated, so I ordered upgraded equipment.

When I go into my Xfinity account, both TV boxes are listed as "status unavailable". I can't perform a system refresh because it says I have no main TV box. I've never had a "main TV box", I've only ever had the two TVs hooked up, one with a bigger box, and one with a smaller box.

I got my new X1 boxes today, and I tried to hook up the box for the living room TV first, as that's the one that isn't working and I didn't want to mess with the TV in my bedroom that does work until I get the other one fixed. I got the box hooked up correctly, and I got to the Welcome message, but I'm getting stuck on the Welcome screen, and after a few minutes it gives me the error code RDK-03013 and says to check the cable connections and restart the box. No matter how many times I recheck the connections, and restart the box, I cannot get past this stage.

I tried the Xfinity Assistant, and got to the part where it was checking the connection and to please wait. It could not find the connection, and then it said it found an issue that could be affecting the connection and to press "next" to continue, and then it got stuck in a loop where I would press "next" and it would repeat the "press next to continue".

This is driving me crazy. I can't get anywhere with the Xfinity Assistant, and I can't find any articles in the help section that are useful either.