I cant stand xfinty any more the cause me so much stress and the customer service is soo disgusting and horrible

Im at my witts end with xfinity  my land line service was broken for 3 weeks, i took me  a week to get someone to call me to schedule a service appointment. I received the appoint email, took off work and they didnt show. This is not the 1st time ive had poor service with xfinity all the app does is run the customer around in circles, i feel the goal is to wear us down so we give up. I decided to cancel my service , it took 3 days to get someone to call me back to cancel and they offered to help me to convince me to stay with xfinity. Stupidly i agreed. They schedules another appointment (i am now on my 2nd week with no land line) he comes out and fixes it, the next day it stopped working again (this is also after n u m e r o u s trouble shooting techniques and 2 brand new modems. I decided again to cancel service, took 3 days to get a call back, they retention dept offered me a $140.21 credit on my bill to keep me with xfinity for the 2 days i took off work and the landline service not working for 3 weeks. Again i stupidly agreed. They assured me the credit would be placed on my account and then transferred me to tech supporty who fixed my land line over the phone, the next day my bill is emailed to me and the credit isnt applied, called and basically was told that they see no record of that amount and cant credit me that amount after over 20 mins of arguing with them i told them i have had enough and that i will cance my service and hung up. Ive tried to cancel it and ill get is sent around and around in circles and will not allow me to schedule a call back (just gives me an error) so i cant even cancel my service, i have since removed as auto pay from my account so that they cant take the money out since its not what i agreed to and i want to figure out how to report xfinity either to the ftc or fcc or bbb not sure which. I can no longer handle the disgusting customer service they provide not can i tolerate the lies and the amount of time have to take out of my personal life and my work life whenever there is a problem my entire day  is ruined everytime i deal with xfinity and this is just one of m-a-n-y days this is happened. [Edited: All Caps]