$60 to $70 Xfinity Internet price switch up 5 year lock

I signed up for service recently through chat. The offer was too good to pass up. I had seen the 400 and 600 speeds for 55 and 70 respectively for the new 5 year lock as a new customer.

I clarified, asked several times and the rep showed the 29$ new service discount and a $10 auto pay and billing discount. I was eager as I was moving into a new place, but the agent confirmed he understands I see a $55 or 70 price but said there is an additional $10 price discount that I would be eligible for. I signed up for 600 at $60 for 5 years which was quoted. After wards he helped also switch my phone providers and also assisted me switching over my phone, which was included in this new customer deal. He told me once I activated my Internet I would get the $60 for 5 years adjusted bill as they can't offer a discount until I signed up and the payment they charged me ($25) went through. Which took roughly 3 days. Also, my address was Internet ready and so I didn't need the technician, but when I tried to activate it, the agent figured out that I need new lines to be sent to my home and so I needed a tech for which now I have to pay $100. (Should've taken a hint then and cancelled it). 

Low and behold, on the 4th day when the bill finally generated, I see $70 bucks a month as my "regular monthly charges". So my wife and I, totally bemused, started looking at if this is common. Not only is this common, but we found so many of the same situation. Not only that but it's the same price point. Also, in almost every case the agent always said that the discount is available "when the bill will be available". And almost every time Xfinity apparently takes 3 days to "update account". Is that a coincidence? How is this legal? Thankfully I took screenshots and videos, in addition to the "transcript download feature" which is a glitchy nightmare. 

So I go to a new agent after 3 days, and he flat out says the agent made a mistake. I said I clarified 10 times there was no mistake. I have it in writing about the discounts and service price promised. He says can't do it it's a mistake. I told him to allow me to send screenshots and videos. Disconnects the chat. And so does the next one. 

How does one get a solution here? considering I am a new customer and within 30 days can I just null and void my new service?