COX says to call Netgear - Netgear says to call COX

For cable modems, firmware updates or a push has to be initiated by the ISP. 

Before you get in to that argument with your ISP, you can log in to your modem and determine what firmware version is currently istalled.  I have a different model Netgear modem, but the information is provided under the Advanced Home tab.  See attached screen snip.

Then you can go to this link and determine what the appropriate version of firmware is available for your modem.  Here is the link:

Netgear Cable Modem Firmware   See attached screen snip next post.

It is not unusual for cable phone support personnel to be totally clueless on how to handle user owned modems.  You may have to be very insistent to get a next level support person to help you if the firmware on your modem is different from that listed on the Netgear site.

If the firmware on your modem matches what is on the Netgear list, you will need to look elsewhere to resolve your issue.  The FSE was just providing lip service.