Service issues for months

I’ve had continuous service issues for the past three months. I’ve called in numerous times, been escalated to the top tier of tech-support, had multiple visits to my house. I really thought I had gotten through to someone the last time I spoke to a supervisor. They said they were sending out a technician that was actually from Xfinity and was a supervisor that could see my history and help me. Instead, another contractor showed up, saying he couldn’t see my history and couldn’t find a problem at the moment and couldn’t do anything for me. I can’t even cancel because I can’t understand the people that I am talking to and they keep just trying to upsell me on a service that doesn’t work. I don’t know what to do. I’ve asked for boosters and better tech help, but nothing is working. I just want to speak to someone in the United States about the problem to see if it can be remedied or if I just need to cancel. At this point, I can’t work from home because I can’t use my phone or my Internet in my office. Both are through Xfinity.