xfinity tried to trick me into getting a mobile line

I  am in the process of downgrading my service to internet and 3 streaming channels only, eliminating other tv channels, which I will get through YouTubeTV.  But when I couldn't get plan confirmation I was directed to call a customer service number. While on the phone my internet went out. The agent took me through steps to correct it, using my mobile phone. I thought he was talking about using an iPhone hotspot, but instead he signed up for a mobile line! I  told him I absolutely did not want the mobile line, despite his assurances "it won't cost you one penny." Fortunately, as soon as realized what he had done, I cancelled the order, via chat. The phone agent asked why I didn't want a "free" service. I answered because of my experience with xfinity cable. This service won't be free forever-just as the "great deals" I got when I started cable, quickly disappeared and rates skyrocketed. Why would I think mobile would be any different?  While the mobile line has been cancelled, I want to register my complaint about the attempt to trick me into adding it and also to warn others about this predatory sales practice.  Honestly, if Xfinity wants my mobile business so desperately, they would need to prove via their cable tv pricing