Concerned with misleading sales practices/incentives and lack of accountability and service

I expanded my relationship with Xfinity and added mobile service for my family.  My decision was based on receiving $500 for switching to Xfinity, which helped offset the $700+ payoff amount needed to leave AT&T.  I did all this work in the Xfinity store with the representatives, including helping me payoff the phone and complete the incentive process online.  I never received the incentive and have since been told that no such program existed or I needed to go back to the store.  The store says they cannot help me further.  They directed me back to the phone reps who confirmed after 6+ months that I appear to be eligible for $200, but not $500.  Anyway, I find this type of sales practice unacceptable.  If someone at Xfinity wants to review my situation and learn about what I experienced, please reach out to me.  I also have unanswered emails to share that I wrote to the store rep who initially handled my account trying to address the situation early on.  My goal is to try and reconcile and expand my relationship with Xfinity, but I feel compelled to move on to another provider soon given my concerns of service and sales ethics.