trapped in service with increases

So about two years ago, I purchased a phone for my daughter through xfinity. I liked the service, so I switched 3 more lines to xfinity, with all new phones. This past year, I moved to Colorado where there is apparently no xfinity service, resulting in my having to cancel my internet and cable services. My issue, is that in the past two years, my phone bill has gone from around $360-$370 to around $450-$460 a month! First they hit me with extra fees because I no longer have xfinity home service. I get it, but it’s not like it’s my fault that they don’t offer the service in my new town. (I actually called to check if they did before I moved and was assured that xfinity was an option here, however it wasn’t, I found out later) also, I can’t really explain how the bill has gone up to high so fast. Can anyone help me? I struggle with this bill every month and cannot pay off all four phones because I simply don’t have it. And xfinity refuses to move my payment date, I’ve tried. Does anyone know how to get out of service with them? One of the lines is for my mom, and she would like to keep the service but she doesn’t have xfinity home service and they won’t separate the lines. They don’t work with you at all and I’m afraid they will keep increasing my bill. Any help is appreciated.