United Airlines United Explorer Mileage Plus Card Failed to honor advertised credit Nationwide

I tried booking a flight through United's website having been recommended to their offer which was, if booked and paid for using their United Explorer Mileage Plus Visa card I would receive a statement credit of $250. With this in mind I applied for, and received said card. After receiving it I went onto the United website where I selected a flight and then came to the payment section where I filled out the details from my new card. As I did not see any reference to the statement credit, although there were a couple of boxes requesting any promotion codes, I wondered if I should fill those out, so I called United before hitting submit. The CS rep explained that the $250 statement credit did not need a promotion code as the credit would automatically be applied to the next statement following an initial purchase. I asked if they could confirm that in writing and they transferred me to another department, which was Chase Visa I believe. The Rep again confirmed that a statement credit would be issued on the first statement and again I asked for written confirmation and was told that they would have to transfer me to a supervisor for that. Supervisor came on the line and told me that the statement credit would not apply to the particular card I had. I drew his attention to the online webpage ads and to the fact that the card as issued looked identical to that shown and that was what I had applied for, but he still refused to honor the offer. Following this I have no confidence in either United or their Chase partners as far as I am concerned this is fraudulent advertising.