Spirit Airlines Fraudulent advertising

As I was about to complete my reservation for tickets to Costa Rica the spiritair website presented me with an option to lower my fare by $40 by applying for a credit card. I then applied for the card during the same session; however, NO discount was applied to my final cost. I then got an email saying I was approved for the card but still no discount. I complained to two different people at SpiritAir over the phone but both gave me different answers. One says that I get the discount on my next flight and the other says that there must of been something in the fine print that I did not see. I told them both that the website explicitly states I will get the discount for the current flight but neither could give me an answer and neither allowed me to speak to a manager.