Xfinity Mobile complaint

I was lied to about a promotional deal Xfinity Mobile offered me to transfer my cell phone service to them. Because I am an existing internet customer, they told me if I bought a new iphone that I would get 1 year free line service, meaning my bill for the first year would only be for my iphone payment. Xfinity did not apply this promo to my first bill. When I called to ask about this, they told me I was sold a promo that I was actually not eligible for. After hours of calls, talking to multiple reps and different depts, opening case #s that were ignored, they still have not resolved the issue. I believe that they know they are using deceptive practices to gain new customers because of how my issue was treated, continually handing it off to someone else with no resolution. I was even given contact info for their corporate escalations dept and still no one attempted to correct this.