Product: Credit card or prepaid card

I applied for American Express 's XXXX  card on XX/XX/XXXX and successfully got direct approval without experienced the pop-up window. No pop-up window appeared during my application meant I was 100 % eligible/valid for the welcome offer they offered at that time. ( The welcome offer was XXXX  points rewards after spending {$5000.00} within 6 months after opening account+XXXX points at U.S. Gas Stations & U.S. Supermarkets ) . I also got confirmation from their online agents that my welcome offer was already connected to my account and was thus always active ( refer to the chat history in the attachment ). I've spent {$5000.00} within the given time frame and thus received the XXXX points. However, recently I just realized I haven't yet seen any 10x points rewards posted to my account for those of my eligible purchases at U.S. Gas Stations & U.S. Supermarkets have made since my card was opened. Considering my case, I contacted their agent online again on XX/XX/XXXX to ask why I haven't received this part 's rewards for over 3 months, but then I was informed by the agent that the welcome offer WAS DECLINED when I was doing my card application online with a pop-up window show-up for detailed notification. Therefore, I can not receive my welcome offer anymore and what I have received ( XXXX points ) should also be removed from my account. However, I NEVER saw/encountered such a pop-up window to warn me that the welcome offer can not be applied for me when I was about to submit my application. My card application went pretty smooth and nothing strange like the pop-up window happened during the procedure. Unfortunately, their agents insisted I must be experienced the pop-up window for my application and said they can not apply that welcome offer to my account anymore. And they even said the deposited XXXX points will be taken from my account as well. I've been following with them for my specific issue for over 5 months since my card account was opened. 
On XX/XX/XXXX, I contacted AMEX through online chat and the agent told me the raised investigation was ended ad the outcome was the welcome offer was still eligible for my account and I should receive my missed rewards described above within 12 billing cycles and I simply believed them after that time and still used my card for gas station and supermarket purchases as they told me my welcome was still there. However, on XX/XX/XXXX after two billing cycles, I still hadn't received my missed rewards as they promised compensation time frame so I directly called them and also chatted their agent online again to see what was the problem but they told me that their system still denied my welcome offer ( which is opposite to what I was informed on XX/XX/XXXX ) and they won't add the missed points to my account. It was totally ridiculous, shameless and of course unreasonable ... They played with me from time to time and I had wasted a lot of my precious time to patiently explain what I actually encountered but in fact, they never take this seriously every time and my patience ran out after that. Therefore, I'm here to ask for help to see if CFPB can protect my rights. 
The reason why I applied for this card is because of the attractive welcome offer. The fact of the non-appeared pop-up window but marked in the system is for sure the technical problem/internal unknown issues of AMEX 's own website and it can not be the customer 's fault. I would not apply for this card if I saw the pop-up window about the invalidity of the welcome offer towards my card application. It's simply a cheating behavior from AMEX and I strongly insist that they have to add the welcome offer s to my account and can not remove them because of their own technical issues or internal unknown problems.