Terrible to no-existing cellular service with no solution

I have had Xfinity mobile service for over a year and have 3 lines. 1 of my lines has not had decent service this entire time. Most of the time there is no data, no ability to send or receive text messages or phone calls. I have called over 40 times and wasted at least an hour up to 4 hours with support. I get told it is being sent to the advanced team but nothing has been improved or fixed. Most of the time they don’t return promised call backs and I have never been given a discount or solution. In the last 4 days I have called been given a ticket number and of course told the advanced team was working on it and changes were made to that line so I have to wait 24-48 hours and if no improvement the next step is a replacement device. This day 5 hours in total wa spent on the line with support for myself and my son as it is his line. Waited the 48 hours and there is no improvement in fact it is worse. I have been hung up on, told the ticket is non-existent so cancelled. I called back and the person who said there is no ticket number put me on hold after 20 minutes of giving the history, he just placed me back in the waiting room because a new person answered and it started all over again. 
this is the definition of insanity, round and round we go same step’s every time with no improvements. The service person insisted he had to call the line and speak with my son so he could give him directions for the same step’s performed 100 times over, restarting the cellular connection, changing/checking settings etc. I finally yelled this is enough. What don’t they understand! The line has no working services it cannot be called! My son has to go to a restaurant with public Wi-Fi to have any chance of his phone working at all! He was there for hours numerous days in a row. I explained what has been tried but it doesn’t make any difference they want to it over and over for no reason. 
I have not been offered any discount or bill credits for the lack of service only treated badly and told to have him call when he gets service. I have stated the process of switching to another provider 

it is not right to continue charging someone full price for a service you are not providing! Worst customer service experience I have ever had, wasted too many hours on hold or troubleshooting a device the exact same way and changing or checking settings that have been verified minutes earlier, I would not recommend mobile service through them.