Mobile and internet billing issues

I bought cell phone from xfinity and the agent told that I have to keep the srevice for a month and if I pay the full price of the cell phone, I can unlock it and cancel the service and get differnt service privider.  I followed her instrution, then after a month I cancelled the service and unlock my phone. Then I took differnt service provider and then got another monthly bill from xfinity mobile for the canclled service. Such a annoying thing, I spent money and hours of my time to make sure by talking to dfifernt agents, and xfinity agents don't even know what they said. Total waste of time and money and lots of hassles.  Then I again contacted the customer service by calling and also thorugh chat and waited 4/5 hours in total to connect to an agent, once connected the agenst started talking non scence, then after arguing for hours, he told he will waive the charges which will be waived in 30/40 minutes, after even 24 hours, I can still see the charges on my account. Now I am calling and trying to connect to an agent for again 2/3 hours but still waiting in line which is showing 0 queue for two hours and could not get connected yet. Now, the internet bills went up without getting any notification. Again trying to contact the agent but same thing, waiting hours for two days and still on line. Such a hassles I am having by taking these two services from xfinity.  I think it is not worth to have xfinity at all till they fix these frustrating issues.