ISP (RCN) won't update firmware on C6300 (AC1750) Modem

I have a C6300 AC1750 Cable modem router that has older firmware on it (currently running V1.02.21) that I'm trying to get updated to the latest version. The issue I'm running in to after reading the forums posts is that I needed to contact my ISP to have them push it. I've spoken to my ISP (RCN) and submitted several tickets with them asking to have it updated as they are the ones who are suppose to push these updates out. Unfortunately, they responded with saying that they "do not push out firmware updates to customer owned equipment and it's done by the manufacturer." 

I'm not sure how to proceed here, as I don't think Netgear can push out the firmware upgrade to my modem, and as it seems from my ISP, they aren't willing to do so anyway. I already stated in my ticket that I reviewed forum posts from here from NetGear agents basically stating its done at the ISP level and they just ignored that entirely and are refusing to upgrade my modem...