I feel scammed by the customer support chat team. Who do I contact to for an actual complaint?

I have both Xfinity mobile and Xfinity Internet. I contacted your Internet support team through chat asking how to lower my bill when the monthly cost increased.  They told me that I would be to enroll in some promotion that came with an iPad. I expressed MULTIPLE times I did not want/need an iPad. They pushed and started it was just included in the promotion and there would be no charge for it.  I later find out that I actually have been paying for this iPad because they put it onto my Xfinity mobile plan and now I'm stuck making device payments for something I did not want. 

I also reached out to the chat team regarding my mobile services and was told multiple lies there too. I downloaded these transcripts and I need to v make a complaint.