How do I switch Towers to better my service

I have had Xfinity Mobile service for about a year now and we have had problems with our service dropping calls. Not receiving texts until we move the other end of the house or reboot our phones 3 times in a row. I called in about this and customer service helped me to switch towers. It worked for a while now we are experiencing the same problems again. BUT this time when I call no one seems to know what I am talking about or how to switch towers. PLEASE HELP.