How to file a complaint to corporate

I called Xfinity for one thing and was asked if I was using my Xfinity voice line. I explained that I did not have a phone connected. Was told that they would send me a phone and I would save money every month and not have to pay for the service. When she asked me for my credit card number ($16) I yelled out that I didn't want a phone or additional bill. She assured me that it would not be an issue. I called back a little later to add video recording to my security service for $10/month. 6 weeks later I noticed that I had an autopay with Xfinity Mobile (never signed up for autopay for this service) and I would be debited $50. Additionally, my regular service bill increased by $65. Began calling last week about the mobile service. Someone lied and said that they would take care of it and that the person who set it up was wrong. I let him know that when the transaction was taking place, I objected several times and continued to be reassured that nothing would go wrong. He told me he fixed the issue and that I would receive an e-mail. 8/13 I noticed that the mobile bill was still there, and I called back. This time I was provided with a means to return the phone and cancel the service. I mailed the phone off 8/14 and informed that my bill increase had nothing to do with Xfinity mobile and I needed to speak to customer service. I was transferred and when I began to give a breakdown of my problem the phone disconnected, and I was not called back. I called today and noticed that not only was my bill higher, but they removed my Xfinity voice altogether and I was paying more for less service(s). I spoke to one representative that raised her voice on me. Then called back and was escalated to a supervisor when the representative realized she could not put my services back to where they were without raising my bill even higher. In the middle of the call to the supervisor, I was disconnected again and not called back. On the last call, I was told that they could add voice back, receive a $120 credit (spread over 12 months) you do the math and that my bill would be $20 more all for a mistake that Xfinity made with someone who should not have been selling a service. And a mention of an investigation. When you can't call someone back when the phone is disconnected. Even though it should be recorded that I was trying to cancel, and they totally misrepresented the service and nullified promotions that I already had in place, increasing my bill permanently. I would like to escalate my issue because I do not believe there will be any investigation and that I am stuck paying for something I never asked for and tried to prevent. I did not receive any customer service. I felt like they gave me something that was lower than the original bill and for me to basically go away. When I submitted a survey with zeroes someone named Janice called me but only let the phone ring twice and sent me an e-mail. I responded with everything above minus the so-called resolution and no response. This is unacceptable. I have been a loyal customer for almost 20 years and do not feel that anyone truly wanted to resolve the issue.