"Internet is offline" in Xfinity App but connection IS working. However, connection is intermittent and speeds vary wildly. HELP

My Xfinity app says that my internet is offline, but my connection is online. This is making it nearly impossible to troubleshoot through the app or through the automated phone services Xfinity provides. Service is continually sending me through a loop to reset my modem but that is NOT the issue. I'm desperate to speak to an actual person. I have tried everything, from firmware updates to the devices, driver updates across machines, to direct connection tests and resetting / unplugging and re-plugging the modem and routers multiple times, over multiple days, spanning months. It's impossible to get hold of an actual person to solve this and I'm considering switching providers. 

I pay for 1200 Mbps internet, but never experience more than 100-300 Mbps in spots even when connected directly over ethernet. My internet connection has been falling off completely, down to a few kbps, at random points throughout the day. My wife and I work from home and this has been incredibly disruptive to our business. I'm constantly being kicked / lagged out of meetings and calls, video glitches, voice is delayed, shows stop streaming, and the kids can't game without getting booted from games. I should be receiving a premium experience at home for what we are paying. 

In a nutshell the problems I am experience are:
1. Internet is nowhere near performing at my service level, when it decides to perform at all. 
2. I can't get help with the issue because the Xfinity app doesn't even recognize my modem is running. It think I'm offline when I'm not and so does automated support
3. Internet randomly comes to a halt throughout the day, and only returns when I unplug and re-plug the modem and router. Once it comes back, I am back to problem 1. When I try to troubleshoot, problem 2 kicks in. 

Please, please, please connect me with a real person.