My account is all messed up

I recently had internet under my ex girlfriends name here at my apartment. When she moved out I started my own account, signed up for internet and was approved for xfinity essentials. I turned the old router in, got a new one from the Comcast store in town and registered under my own number. Now when I tried to activate my device it constantly shows up as not connected and will not activate. I cannot get an agent it anyone else to understand what my problem Is they just transfer me around until I finally get dropped by the automated system. It has been like 4 days. I am going to LOSE IT. This has been a COLOSSAL waste of my time and energy. The guy at the Comcast store promised this would not be a problem. The online agents and the phone agents do not speak English and you can't even call the store. But hey anything to save a few bucks huh comcast. I know you think that unplugging a router for 10 seconds fixes every single problem across the board but I hate to tell you it doesn't.