billing loyalty department discount xfinity home internet

I received a discounted rate from a "loyalty dept" representative over the phone and even completed the electronic confirmation. 3 days later the discount suddenly vanished. When I called the 5 year rate had suddenly been reduced to 3 days and was no longer available. I was offered a new discount for less savings and only 12 months. I should receive the rate and time length that I was promised. I am a long term account holder and would not have to pay almost 50% more than what is being offered to new subscribers. The details $50 mo 1gig internet five years to new subscribers. my current $85mo 1gig 5 years, my original offer $70mo 1gig 5years now pulled and replaced with $75mo  1gig 12 months. this is unfair and does not respect your longterm customers. I request that you honor your commitments