Xfinity mobile issues HUGE discrepancy in expected Vs actual bill

Our mobile bill is not even close to what was communicated to us during the start of our mobile contract. We have two phone lines. 

1. Line one was supposed to be a free line for a full year - September 2025 - September 2026  that we redeemed as an Xfinity platinum member and that xfinity promotes so heavily. It now shows up as a paid line. We checked with the representative multiple times that due to moving states, we might switch internet providers and that it would not affect our Xfinity mobile line. We were assured that it would not.

2. A device and line through Xfinity which was also heavily advertised as a great deal was supposed to receive two credits.One $400 device credit. And one $300 credit for being a platinum long time xfinity customer through a coupon code. We confirmed this multiple times with the representative at the time (since that's the only way to afford this ) that this would be IN ADDITION to the $400 device credit and was assured so. 
The HUGE discrepancy: The initial estimate on the website for the device plus line for this device was $31.94 and current bill shows $49.44 plus a $25 standalone mobile customer fee we were never aware of when we cancelled our internet account. 

That is a $80-$90 jump in monthly payment and is unacceptable.

I want to emphasize that our only source of information in these cases are the representatives that process our orders and we are not responsible for additional billing burden if they don't provide us with accurate information since the app does not show any such constraints or information.