Horrible experience with xfinity chat agents.

I contacted Xfinity using the chat on the app and talked to an agent about an hour ago. I wanted to cancel my mobile line because I am leaving the country and asked them to do it by the end of the month. During the chat they got confused and asked about my cable service several times. When I called attention to that, they said it was a typo, but clearly they were confused between chats and distracted. I asked them to cancel my mobile line by the end of the month. Instead, they did it immediately. So now I don't have a working mobile phone. When I complained they disconnected. Another representative then talked to me and blamed me for what happened. Then they asked if they could call me to my mobile number, yes, the same number that they deactivated by mistake. I am upset, and I have the transcripts of the conversations but don't know what to do to raise a formal complaint. I spent about an hour talking with different agents, and no one was able to help.