Netgear CM3000

I recently decided on and bought a Netgear CM3000 modem because it was on Cox's supported modem list.  After attempting to find the page to simply change to the updated MAC address of the new CM3000 (which took some time to find, had to use Google search) which lead to the "activation website".  The result was to show Netgear CM3000 is not supported.

Did I just get scammed into spending money on an unsupported item they lied about being actually supported, or is there another problem happening here?

The new (still unused) and current 5-year old modem being replaced are both my own equipment, rented.