I would like to submit a complaint and not have to deal with the Xfinity assistant/agents

I am very frustrated with my experience with Xfinity and I would like to submit a complaint to someone who is able to assist me with these issues. I have dealt with customer service agents since I started with Xfinity and have been lied to or jerked around. I have spent way too much time chatting and calling agents only for the information to be inconsistent and the charges to my account are way more than what I agreed on. So, I would like to contact the appropriate person and share the downloaded conversations so they can see what I have been dealing with rather than me explaining and explaining over and over again. I got a well deserved credit of $240 for the home security cameras that I continued to be charged for when they should have been taken off. This credit brought my bill current while I tried to cancel my entire xfinity service. Well, the retention team lady, Rose, was too busy trying to upsell me after explaining I do not want to continue with Xfinity. Now for some odd reason I owe $149 shortly after my account was credited and I was in the process of cancelling. I was also promised a refund and I am now being told they cannot do that. So please, help me file a complaint to the appropriate department where I can attach the downloaded chat histories. 

Thank you.