4th time trying to enter complaint

"Since you have already have two lines with Xfinity if you add another line the Xfinity mobile bill will remain the same. And the Google pixel 8 is also completely paid by Xfinity, there will be only One time Federal sales tax for the device apart from that there is no charges." This is the rep explaining to me that the "free" phone will cost nothing. Numerous times I was promised no additional charges on my plan. Lo and behold im being charged for the phone. What am I missing here? Is this an outright dishonest, misleading business tactic to trap unwitting customers into paying more money? Should I be looking elsewhere for my mobile service?