Modem/Router Connected but not Internet Connection

My Xfinity service has never had an issue until now. 2 days ago my service just full stopped while I was watching tv. Naturally I checked online to see if there were any reported outages in my area. None. I power cycled my Xfinity modem. No effect. Tried restarting from the app, no effect. I moved the modem into another room and tried a different coax connection, no change.

I checked all of my coax runs and they look ok. The modem boots up seemingly normally every time I reboot it. All the correct lights show up: Power, US/DS, Online and then the 2.4GHz and 5GHz begin to flash. It broadcasts the network but there's no internet connection.

I went into the Xfinity store and got a new modem just in case my old one had died or something. Set it up and the same issue. No internet.

I called Xfinity support and they make me do all of the steps I have already done 3 times+ for an hour. I then get an appointment scheduled for today at 5pm and then they cancelled the appointment with no warning at 11am and say "All Good! It's fixed!" It's not fixed. I have no internet connection. What is going on?

The odd thing is that it seems Xfinity can communicate to my equipment, but I just have no internet connection. So that tells me that the coax connection must be fine. The Xfinity app will show "You're Online!" but clearly that's not the case because attempting a speed test CLEARLY shows that the download speed is ZERO.

It's almost as if someone at Xfinity pressed a big red button that only stopped service to my address. There has to be a fix for this from someone at Xfinity.

Xfinity refused to restore the appointment for today so I have to go another day without service.

I have an appointment with a technician tomorrow.

Has anyone else had this issue? If this gets resolved tomorrow I will need to know what happened because this is completely unacceptable to me and I can't chance this happening again in the future. I need to know what keyword to tell support so that they understand what is happening.