200 Rewards Card

First, I'm upset with at&t. I left and came back due to a mailer I received saying comeback and receive a $300 rewards card. The customer service rep I spoke with was great. She was so nice and helpful. So when she told me I couldn't get the $300 rewards because I didnt want to add cell phone service I wasn't upset. I qualified for the $200 for my uverse tv & internet.  I recently contacted customer service about the rewards card and was transfered to three different people. One lady said she couldn't access it and transferred me. A guy said he saw the rewards card hadn't been sent and put me on hold while he tried to send it out. After holding twice he told me he needed to transfer me to another agent to get the card sent out. After explaning my situation for the third time to the last rep she asked me to hold once again. After waiting she said I only have a $100 reward on my account. I advised her that was incorrect due to the mailer stated $300.  I explained how I was told when I signed up I qualified for a $200 reward card. She started cutting me off when I was talking. We went back and forth amount the amount a couple of times. Realizing I wasn't getting anywhere, I told her not to do anything to my account because I knew the rewards amount was wrong. I'm so fustrated. I guess returning to at&t was a bad decision. Any suggestions on who I should contact would be greatly appreciated!