Sometimes customer service gives OK advice
Update on the cable-modem situation. I ended up getting a new Motorola last week and it has actually allowed me to get faster connection speeds. Who knew!?!?!?
Also, I haven't had problems with the connection being down - but I'm unconvinced that's completely because of the new cable-modem rather than the problems with the infrastructure being resolved, but hey because of the faster speeds I'm still happy.