Lied to about promotion

My post was deleted for some reason after posting, and I have no idea why.

Today, I was called by an Xfinity agent saying that I was eligible for an Internet upgrade from Gigabit to Gigabit Extra with a lower monthly payment if I agreed. I asked her to email these details in writing after our call, to which she stated that I would receive an email 5-10 minutes afterwards. I didn't receive any email at all, even after several hours. After this happened, I contacted an agent through the online chat, and they confirmed that this promotion doesn't exist and that my monthly bill would be increasing due to her upgrading of my service. I was on a promo that was $50 a month for gigabit, and she stated that my monthly bill would be lowered to $30 a month for Gigabit Extra. I checked my account bill and it shows that my next bill is $93, so my bill increased by a massive amount of almost double. I then spoke to someone on the phone, and they confirmed that the first agent lied to me (this is all on a recorded line, according to the agent I spoke to). I asked if they can just return me back to my old promotion and monthly payment and service, to which they said it is not possible for them to bring me back to that promotion. So now, my only option is to pay the regular price for Gigabit when I had 1.5 years left on my $50 a month promotion. I have been told that there is nothing that they are able to do for me. This is unacceptable that this was a fault of an Xfinity rep and now I have to pay a massively increased monthly price, and I have asked to speak to someone higher that could fix this situation and they just repeat that there is nothing they can do. 

Is there any recourse that I can get back what I was contractually signed to until I was lied to by a shady Xfinity agent?