COX Internet Issues

So I previously had COX's 150mbps plan. I am in the Military and due to certain issues i had to cancel my plan and ended up upgrading to the 500mbps plan. This has been the absolute worst month i've ever had in customer support. I currently have the Netgear AC1750 Router and the Netgear CM1000 Modem. I called COX and asked them why i'm not getting 120 mbps download over 5G and they sent a tech which said my equipment was at fault. Shortly after i contacted Netgear and they said it's due to COX not having my modem on the correct firmware. My modem is on V6.01.07 and based off of the website it's supposed to be on V1.01.03. I called Cox and spoke to 5 different people and none of them know what to do to fix this. has anyone else had this problem with overpaying for internet you haven't received?