Issue with billing/quote

I was given a quote multiple times on Xfinity chat for my current package, told to pay that amount and my bill should be updated within 1-2 business days. They have yet to honor it and continue giving me the runaround. It's been months and I am still battling it.  I have contacted FCC. Any other suggestions to get this resolved?  I continue to do online chat. Some agents say they have escalated it and will get it handled, others say too bad. I have all chats saved for documentation purposes.  I feel like they have scammed me by quoting me the same price multiple times, but yet won't honor it even though I have it all in writing.