Cellular signal

We’ve had Xfinity Mobile phones for more than 6yrs with no cellular coverage issues at all. Two weeks ago we noticed that we couldn’t send or receive any calls from inside our home. People would call and get our voicemail. We would call and it would fail or the person could not hear us at all before the call failed. Friends and family come over and experience the same problem with their Xfinity or Verizon phones. Others in our neighborhood also can’t use their Verizon or Xfinity phones inside anymore. This is a NEW problem that can only be a Verizon cell tower problem. After several 1hr+ calls to Xfinity customer svc, they tell me they’ve fixed it. So try to call someone and no service. I call back and get the same run around. Phone in field test mode shows RSRP of -121 to -126. There is no service here anymore. I asked Xfinity to call Verizon and they refused. Verizon won’t talk to me because I’m not a Verizon customer. Xfinity told me to use wifi calling. That’s not a solution, that’s a work around. I’m paying for cell service that I can’t use in my home. How do I get a Xfinity rep overseas to understand that they need to have a Verizon Wireless service tech come to my area and find out what happened? I asked them exactly that and he called Xfinity Mobile Tech Support. I’m at a loss here.