Product: Credit card or prepaid card

I signed up for a Southwest Airlines credit card through Chase using a link Southwest had sent me in an email about a promotion for XXXX mile bonus offer with its credit card. The promotion required that I apply and be accepted before the offer ended on XX/XX/2021. I received my approval on XX/XX/2021. The requirements for the XXXX bonus miles were a ) spending {$3000.00} within the first 3 months and b ) spending a total of {$12000.00} total during the first 12 months. I met the spending requirements, but I only received XXXX bonus miles. I thought this was a computer error and would resolve itself, so I waited until XXXX to contact Chase. 
XX/XX/XXXX, XXXX I called and spoke with a customer service agent, who put in a request for the XXXX mile bonus offer. He told us to wait 30 days for the additional XXXX miles to be credited to my account. 
XX/XX/XXXX, XXXX I called for an update on the request for the missing XXXX miles and was told that the note in the file indicated that the marketing team researched the issue and found that there had NEVER been a promotion for XXXX bonus miles. I asked what I needed to do to submit documentation of this promotion. I was told to use the secure messaging on the Chase website. 
XX/XX/XXXX, XXXX I submitted a written request for the missing XXXX miles and submitted two articles ( one from XXXXXXXX XXXX XXXXXXXX, the other from XXXX XXXX about this XXXX mile bonus offer. Additionally, I submitted the approval email from Chase dated XX/XX/2021 to show that I met the deadline. 
XXXX wrote a complaint to Southwest Airlines about using Chase as a partner for its Rapid Rewards program and explained what Chase had done. 
XX/XX/XXXX, XXXXChase responded via the secure messaging. This response was vague and unacceptable. 
XX/XX/XXXX, XXXXSouthwest Airlines representative XXXX XXXX politely responded that this issue needed to be resolved with Chase that Southwest Airlines would do nothing to resolve the matter. 
XX/XX/XXXX, XXXX wrote another request to Chase for an explanation for not giving me the full XXXX bonus miles. 
XX/XX/XXXX, XXXXChase responded . The response was vague and unacceptable. 
XX/XX/XXXX, XXXX-I wrote request the expiration date of the XXXX mile bonus offer. 
XX/XX/XXXX, XXXXChase responded . The response confirmed that Chase had not changed the expiration of the promotion, so I still believe I have met all requirements for the XXXX bonus miles. 
XX/XX/XXXX, XXXX called Chase and asked what error I made that I did not meet the requirements for the XXXX mile bonus offer. The agent told me I had made no errors. He said that the department which reviews and approves the applications can change the promotional offer you are approved for. I asked what the criteria is during the application process to change an applicant to a lower promotional offer. He could not tell me. I asked him for the date that I was informed that I had been informed of the change to a lower promotional offer. He could not tell me a date. I asked how I was informed of this change to a lower promotional offer. He said US mail. I requested that this letter be resent. He said this could not be done. I asked for him to send it as an attachment via email. He said he could not do that because of confidentiality standards. I requested to speak to a different agent. He transferred me to a different agent who then told me that the switch to a lower promotional offer is entirely random. I clarified with her that she was saying that Chase did not actually intend to make good on the XXXX mile bonus offer to everyone who meets the requirements. She agreed and said that it is random who they approve for the promotion. XXXX could not give me an employee identification number, but she was willing to give me the following case number : XXXX XX/XX/XXXX, XXXX called Chase one last time to try to speak to a supervisor one last time and warned I was calling to give Chase one last opportunity to resolve the issue about not honoring the XXXX mile bonus offer before I filed a formal complaint with the Consumer Financial Protection Bureau XXXX I was transferred to a supervisor and waited on hold for an hour and a half. I hung up and called again and was placed on hold while I waited to talk to an account supervisor. Finally, I spoke with an account supervisor XXXX XXXX XXXX who said that the case had already been escalated to the marketing department. If they had declined the request for the additional bonus miles, there would be nothing more she could do. I remarked a previous agent read the notes in the file that said the marketing department found that the XXXX mile promotion had never existed. I informed her that I would proceed with filing a formal complain with the consumer Financial Protection Bureau.