Bad Reward Card Information

As it appears along with many other customers, I was promised a reward card in the amount of $250 that I have never received. When I initially called to set up my service with AT&T I specifically asked if there was anything I needed to do to receive my reward card. I was told "no you just have to wait a few months and it will arrive in the mail". This evening I spent 2 hours and 19 minutes on the phone trying to reasonably correct this issue but was unsuccessful. The first representative  I spoke to was very confused on why I had not received my $250 reward card and even asked her supervisor why I had not received my promised reward card. Her supervisor was also confused why I had not received a reward card and they decided to call the rewards center themselves. After being on hold for 10 minutes, another representative answered the phone as if I was a new caller. She informed me that the previous representative had made notes that I no longer qualified for a reward card. After the second representative very rudely told me that there was nothing that she was able to do for me, I asked to speak to a manager. She transfered me to a random department that was definitely not her supervisor. When my 3rd representative answered the phone, she informed me that she was not a supervisor and that I was no longer in the billing department who then transferred me to the rewards center. The first representative I talked to in the rewards center told me that there was "systematically nothing that they could do" which again led me to ask to speak to a supervisor. Although the supervisor was still unable to help me, she said she could transfer me back to billing customer care and make some notes on my file. When I was able to finally connect to customer care, they immediately told me there was nothing they could do. After spending quite a bit of time on the phone with the customer care representative, they eventually came back saying that they were going to offer me $50 credit towards my account because of everything I had to deal with this evening. My next question was what were they going to do about the remaining $200 that I was owed. Once again I was told there was nothing they could do. Again, I asked to speak to a manager and was told that "he is on a very important phone call and there was no way of knowing how long until he would be done." I said that it didn't matter because after 2 hours of being on the phone with AT&T's poor customer service, I could wait a few more minutes. Again they said that there was no way of knowing how long it was going to be until the manager was available and after saying again that I would wait, the supervisor surprisingly became available. He told me that " he was doing me a favor because he really shouldn't have even been doing that." Typical customer service line. After telling him that was still AT&T coming up $200 dollars short, he said that i should stop wasting his and my own time because that was the best he was going to be able to do. I asked if I could speak to someone above him and he said that he was the only one there. I asked him for another contact so that I can resolve this $250 issue and he said he was the only person that handled this kind of thing. His name was Shah Fahad and he worked in the UVerse Billing department. After asking Shah if he thought that this was my fault for not receiving something that AT&T promised to me in their sales pitch, he responded "No" which leaves me to pose a question to AT&T. If this is not my fault and  so many other service representatives are unfamiliar with what they are selling and offering, why am I not receiving appropriate compensation for not only what was promised to me but also the 2 hours and 19 minutes I spent on the phone with, for the most part, very rude and unhelpful AT&T customer service employees. Please let me know how we can resolve this issue.