Cisco RNG 100 - Self activation won't complete / first time cable tv user - XFinity

We received the self installation kit for our cable modem and cable box on 1/25/17. We are the original residents of this house (built in 2011) and this is our first time owning cable (just basic service). We have been an xifinity customer since 2011 for their internet.

I was able to boot up and use the cable modem, no problems.
However, when I went to get the cable box booted up (model cisco rng 100), it had a blue screen saying this settop box was not authorized for use and to call a 1800 number. During the evening, I had two separate chats and an online text convo with xfinity reps who sent me refresh signals and reboot signals. The box will reboot, I'll get the welcome to xfinity screen with a 5:00 timer and the system appears to start loading. The On Demand loads and at about 2:40/2:30 left, the screen goes black. (at some point before this time period, the lights on the front of the box go out as well, no power light or data. This happened over and over again. If I hit power, the blue screen comes back. I unplug the power cord and plug back in and it gives me the welcome screen all over again, never completing the process. The online reps tried to offer a tech to come out but the scheduling didn't work out for me or my husband. I may have to have a friend be at my house to open up and oversee the work if we really need someone to come out.

My questions
--is there a "trap" preventing the cable signal to complete the download process? Since I haven't had cable tv at this residence, only internet service?
--is the cable box a dud and I should replace it? That would be quicker for us since a tech's schedule and our schedule won't work out until next week.

I hope someone else can answer this. I don't want to run through troubleshooting again.
Help, please?

This question, "Cisco RNG 100 - Self activation won't complete / first time cable tv user," is about XFinity-Comcast TV television equipment.

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