Device ceased working. Wifi still detectable but no internet, router 'not found or supported'

I haven't really had any issue with this device in the past. However, as of a few days ago, we basically just did not have access to the internet for some reason. Whenever one of our devices accessed the wifi, it would connect as usual but we would get no internet connectivity. A few weeks ago a visiter's laptop was having an issue accessing our wifi so I went to http://192.168.0.1/ and changed a setting and got it to work pretty easily. I figured something like this might be the case. However, that address (as well as variants and ones like routerlogin.net/com) fail to load. My computer, which has an ethernet connection to the router, was also not receiving internet. Upon starting the Netgear genie and trying to access router settings, I was given the message "NETGEAR router is not found or is not supported. Also, make sure the device is not connected to the guest network of the router, and no IPv6 is enabled."

Nothing had been changed with the device before we started having any of these issues so I don't see why I'd suddenly be on the guest network. I don't know if IPv6 is enabled or how to disable it if it is. Calling customer service wasn't productive, they just wanted me to buy technical support, and the "self-help knowledgebase" link they sent me was "Router Initial Setup FAQ" which has been of no help.  The only thing I can think of at the moment would be calling the ISP to ask them to update the firmware (which I have no clue if the firmware is up to date or not given that I can't access the device) or just doing a factory reset. The lights on the device all seem in order - the USB is off, the ethernet is flashing, the 5ghz occasionally flashes, and all of the rest are on and solid - so I have no idea what is going on with the device that suddenly we can't access our internet or it. 

I have no intention of purchasing their gearhead support, since we don't have these issues nearly often enough to warrant purchasing a subscription, and it is ridiculous to me to purchase $50 support for a $150 device, at that point I would rather just go back to the Xfinity gateway or take my business to a different company that has better tech support for their devices.