AT&T escalation team please help!! Reward card never received! Nobody can help me!

I was CONVINCED by an AT&T sales representative to sign up for the bundle of AT&T U-verse and Internet (12 month agreement) with the promise of receiving $250 in reward cards after a short 6 weeks. I had my services installed on January 22nd, 2018. After not receiving my reward cards for months, I called and was informed by the rewards team that they were successfully delivered to my address on file and that they were redeemed shortly after. I explained that I live by myself and have a secure mailbox at my apartment home and I’m the only one with a key. They said it was not their fault because they did their job by mailing them out. They gave me a phone number to the visa reward card center and suggested I reached out to them to file a dispute. I called the number and they said as of 5-6 months ago, they no longer have access to accounts associated with AT&T and that I would have to call them back for any disputes. ARE YOU KIDDING ME? I am truly convinced this was a scam to get me to sign up for a service I didn’t originally want. When I spoke to a member of the billing team, they called rewards while I was on the line and all they could say is sorry, the rewards have been redeemed. I feel so scammed and helpless. For some people, $250 is a good chunck of change to not receive as promised! Who can help me make this right?!?