Why does Xfinity fail numerous times

I canceled my internet service a few years back due to it taking three phone calls to get my bill reduced to a new offer so I didn’t have to pay $130 just for internet which seemed very expensive. I’d call and the bill reduction didn’t go through until I called multiple times.  Now this year I requested to cancel my cell service and was assured it was but I’m still getting a charge this month. Now I have to go in person again and spend more time and Xfinity took more of my money. Funny how Xfinity has no problem starting contracts and taking my money but when it comes to reducing a bill or canceling it, it takes numerous attempts. The only reason I stay with Xfinity is because they have a monopoly in my area and there are no other services that work. The government needs to break up these monopolies. Xfinity is the new standard oil.