No internet with Generator backup

At 8:15 today my electric went out.  I checked the Xfinity app and it also showed outage in my area so okay, no internet service either.  I fired up my generator anyway to keep food cold.  My electric has now been out for 14 hrs but the xfinity app shows NO internet outage in my area.  I have my generator powering my office including my Xfinity router/modem, PC, etc.  With the generator powering everything for my home network I still have no internet service even though Xfinity remote trouble shooting shows no outage.  This happens every time my power goes out even though Xfinity tells me everything on their network looks fine.  How can this be ??  I went around in circles with that insane Xfinity assistant robot until I was finally able to get a support rep on chat and that person was completely clueless only adding to the frustration.  At any rate, if anyone might be able to explain this to me I’d really appreciate it.  The entire reason I put my office on generator backup was so I could still use the internet in the event of a power outage and so far it’s been a complete fail every time.  I have hot electrical outlets with all equipment on and no internet even though Xfinity tells me they see nothing wrong. I’m convinced there is power backup somewhere in Xfinity’s infrastructure in my area that either isn’t working or is missing all together.  I’m out of ideas for checking anything else within my home.  Thanks!