billing error

I am having [Edited for inflammatory language] a time getting them to delete a charge that I confirmed I would not be charged for. The agent told me I would not be charged for a technician's visit before they sent one out. I made sure of this. They can go listen to the call. I have had Xfinity for about 10 or 11 years. I am disabled with little money. They opened another ticket. They said they would have it fixed by May 6th. I have just been crying for the last few days. The tickets keep being declined and closed without being resolved, and they are not removing the charge. I have explained over and over through phone and text that I was told I would not be charged by their representative and they can just go back and listen to the phone call to clear this up. [Edited for violating forum guidelines]. I said that doesn't help as I don't have $100 extra, I am on disability. I was told I would not be charged, so I just need them to delete or wave the charge. Is there anyone who can help me? This has become crazy to me that I am still trying to resolve this when I wasn't supposed to be charged for in the first place and was told I wouldn't be. I think they record all calls so they just need to pull up the call to clear this up. I would really appreciate any help.