RBR40 won't communicate with Spectrum modem

Just changed modems (Spectrum Arris). The other one worked fine but a Spectrum agent suggested I get the latest modem because I was upgrading to their Ultra package. After a very frustrating 3+ hours with 4 different online reps who didn't know their behind from a hole in the ground, they sent out a technician. He found out that the new modem they sent was defective! He installed an Arris that is identical to the one I removed but I'm lost as to how to get it to communicate with my Orbi. 

It's been especially aggravating because Netgear keeps blocking me from my account saying "wrong email address or password. It's been the same and is written down in a coded journal. I even tried to change it today as Netgear sent a temporary password....still rejected it. Although I'm 72, I'm far from being senile. Any help in getting the modem to communicate would be appreciated as Spectrum doesn't have a clue. Thank you in advance.