This is almost certainly a configuration file issue. Since we now know TWC is capable of sending a correct config file with activation, perhaps the next step would be to see if TWC can remove the modem on your account, try re-entering it, and seeing if they can push out another config file for the correct modem.
I have rebooted my modem a few times, so TWC is probably still pushing a correct file, at least to me.
The Mac address alone did not seem to be enough for TWC to activate my modem. I had to provide Manufacturer and model number to the person who activated me.
Could this be an issue if some of the other modems were previously activated on another cable provider (without buyer knowledge)? I am not sure if what TWC pushes out throws out any earlier configuration (or perhaps even firmware).
The first time my modem was activated, all of the lights on the front were out for nearly 30 seconds. I am not sure if this is indicative of something more than a config file push.--
Phillip M. Dampier
Editor, Stop the Cap!