Xfinity Bait and Switch

I have recently set up service with Comcast Xfinity. I opted for the $29.95/month 150mbps home internet plan and get a free unlimited line of xfinity mobile for 12 months. I setup both services and after the first billing cycle, I got 2 bills--one for home internet that is $29.95 as expected, but the other was $62.64 from xfinity mobile. I spoke to an online agent, and was told that the charges are justified and my mobile bill is indeed $62.64. I have recorded my phone call with the rep that setup the service for me and the conversation clearly stated that the mobile line is going to be free for 12 months except for a 1 time setup fee of $25. I have then spoke to 2 other agents on the phone and they either avoided my questions or offered a 10 dollar 1 time credit to make me "happy". At the end of both phone calls, they offered to transfer me to someone in mobile who oversees billing, but the mobile reps said there is nothing that they can do as home internet offered the promotion. There is literally no one that is willing/have the power to assist me and sort this out. I am clueless what to do now. Perhaps it is time for me to cut the loss and cut all ties with Xfinity and switch to someone else.