Loyalty making offer that does not happen!

I have been in the process of upgrading my home network. This has involved working with Xfinity teams to configure and troubleshoot issues during this upgrade. I have had serious diffiulties communicating with Xfinity due to language barriers. This has resulted in being transferred to several different groups within Xfinity in an attempt to find someone who can understand fundamental technical issues. During these time I was connected with a "Loyalty" team member (Abby) who proposed upgrading my services to a better 5yr plan of 1.2Gb/35Mb and Unlimited data for $85/mo. After agreeing with this proposal via confirmation link, I was then told that I would not be getting Unlimited data without paying additional cost. Disappointed I selected a different 5yr plan of 1.1Gb/35Mb with Unlimited data for $95/mo. 

Yesterday 2July25, engaging Xfinity in activating a new modem, I again had trouble communicating effectively with an offshore representative who transferred me to another "Loyalty" team person who was very proficient in the English language but not able to address my modem activation. However, she did offer me again, a 5yr plan of 1.2Gb/35Mb and Unlimited data for $85/mo! After explaining the past scenario she assured me that this offer was valid and would be honored. She then sent me a link to confirm this deal which clearly confirmed the details of this plan including the Unlimited data. She also advised I would receive a confirmation email confirming this deal specifics which I have not yet seen. 

I was then connected to another technician who activated my modem and all looked good.

I called Xfinity today to cleanup my account in eliminating the other old modems and asked to confirm the new 5yr service plan which they did verbally but were unable to provide a verification thru the App or via email. 

How do I confirm that the 5yr plan of 1.2Gb/35Mb and Unlimited data for $85/mo will be honored without having to wait until next months bill???

Any assistance is greatly appreciated!