$500 Visa Gift cards For Transferring from AT&T Never Received

I transferred my service on 3 iPhones from ATT to Xfinity with the promise I would receive a $500 gift card for two of the three phones that both had more than a $500 balance to pay off the phones. After transferring the numbers from ATT to Xfinity,  I asked support via chat when I would receive the gift cards. After hours on live chat waiting for them to communicate and get direction from the "advanced team," I received the response I would receive the gift cards to my email on file that day. I did not receive the email so the next day I inquired on the status and was told they would arrive in my email that day. Long story short, they never came. I have a transcript of all the online chats with this communication and verification that I would be receiving two $500 gift cards. I then called and spoke to an agent who confirmed I would be receiving the gift cards in 3 to 4 weeks as it took some time for processing. After receiving nothing in that timeframe, I visited an Xfinity retail store to see if a live agent who spoke English as their first language could help. I spoke with Tadj. After sharing with him the chat transcripts and promises I received, he acknowledged what Xfinity promised, but then said there was nothing he could do about it. I then asked who can I talk to that can help with the situation. He told me no one and that I would not be recieving the gift cards as promised.