ISP Spectrum doesn't know how to update the Firmware of AC 1900 WiFi Cable Modem Router model C7000

I had a similar issue with them recently, seems ever since spectrum took over time warner cable, they have been telling customers it's not their responsibility to update  firmware of customer's modems (in your case modem/router) --  This is untrue!! as the end user have no option to update your firmware and Netgear cannot do it either.  All firmware on cable modems can ONLY be upgraded by ISP.   You need to get to Spectrum's "advance networking support group" to push firmware. It's my opinion they want their "rental fees" for their modem equipment. Eventually they will push firmware, but tier1 support reps won't tell you that.