Product: Credit card

I received a credit card offer from citibank for XXXX XXXX XXXX XXXX XXXX card with a bonus offer of {$250.00} welcome bonus PLUS a {$20.00} statement credit every billing cycle if I spend over {$1000.00} and if I use the AT & T Points Plus card for autopay on my AT & T account and I have that account set to paperless billing. I made the necessary changes in my AT & T account, met the spending of {$1000.00} in a billing cycle, but I have not received the statement credit. I called citibank on XX/XX/year> and the rep told me I was not enrolled in autopay and paperless billing at AT & T. I told her that I was and she said I had to send proof to the following email : XXXX. I took a picture of my account which clearly showed that my last payment was issued with autopay and that my AT & T Points Plus card was the card on file and that I was enrolled in paperless billing. I didn't get a response to the email and the next statement again did not have the credit despite meeting the requirements, so I called again on XX/XX/year>. The rep said there was an issue with AT & T and that I was not enrolled in paperless billing or autopay. I told him that I was and that I had sent proof to citibank. He said the only thing he could do is file a dispute with priority and I needed to wait until the next billing statement to see the credit. On XX/XX/year> I received a letter from citibank with the result of the dispute saying that my account is not enrolled in paperless billing or autopay and so therefore I am not eligible for the statement credit. I called AT & T on XX/XX/year> and they confirmed that I am enrolled in both paperless billing and autopay with my AT & T Points Plus card. I called the citibank number provided on the letter and the rep told me the same thing. I argued that I am enrolled and have met all of the requirements and that I have sent proof to citibank. I asked to speak to a supervisor. The rep said she would connect me and after a wait I discovered that she had transferred me to the AT & T prepaid phone card line in spanish and not a supervisor at citibank. I called back, went through the whole ordeal with a different rep, got the same response and asked to speak to a supervisor, was transferred to someone else who had never heard of the offer and said she didn't know what I was talking about. When I told her that it is on my citibank account when I log in and read it to her she tried to say it was an AT & T offer and that the credit would be on my AT & T bill, but that is not correct. I already checked that out with AT & T and it is an offer from citibank. She said the marketing dept at citibank makes up the offers and she doesn't know the terms or how to correct it. I asked to speak to her supervisor or someone who can correct it and she said her hands are tied, that there is no one to escalate it to and that the best she can do is file a dispute. I later received a letter saying I was not enrolled in autopay and paperless billing and not eligible for the offer. This is totally unacceptable that citibank creates offers to entice customers to apply for a credit card and spend a certain amount on it every month and then will not honor the terms. I have proven multiple times that I have met the requirements and their reps just keep saying that I have not and there's no way to remedy it.