Product: Credit card or prepaid card

On or around XX/XX/XXXX, I spoke with a customer representative over the phone regarding my credit card account. My promotional APR of 9.99 % was to expire XX/XX/XXXX, and I wanted to make sure that my revolving credit card balance was paid off before it was hit with the higher APR after the promotional APR expired. The American Express customer representative on the phone assured me that it would not be subject to the higher APR after the promotional APR expired. I was very shocked because I was sure it would be once the promotion was over. He reassured me that that was not the case, and further went on to explain that, in fact, I could call the company back on XX/XX/XXXX, the day after my promotion expired in order to receive another promotion! I am very upset with American Express because I was given false information. Not only was I charged an interest fee on my account that reads, " Interest Charge on Pay Over Time Purchases '' for the amount of {$110.00} on XX/XX/XXXX, but they also did not offer me a new promotion. I called American Express immediately after the unexpected interest charge in order to ask what this interest charge was for as I was reassured that I would not be charged the higher interest rate for the previous revolving balance that had the promotional interest rate. I had to speak with over four representatives and a supervisor over the course of a week with no success. Not one of them was able to help me out. Each of them refused to believe me when I said that my account was charged an " Interest Charge on Pay Over Time Purchases. '' They told me that there was no such thing on my account and that my card was not eligible for XXXXPay Over Time Purchases. ' I can not even dispute this billing error online because the website will not allow me to do so ( please see attached screenshot 'AMEX billing dispute cont..png ' ), nor was the supervisor able to assist me in understanding this charge, and no one cared to reprimand the representative who assured me that I would not be charged the higher interest rate on my previous revolving balance. All the representatives kept telling me there was no such interest charge and that I was charged this fee for the previous revolving balance that I was told would not be charged! I have even requested a copy of the recording of the phone conversation I had with that representative on XX/XX/XXXX, and American Express told me it would take a few weeks, and therefore there is absolutely nothing more that I can do on my end to reverse this unwarranted charge. I even granted an online chat support representative permission to look at my computer screen, and they still said that that charge does not exist even though it was on my screen in front of me! After four or five phone calls with different representatives and the online chat, I have decided to move forward with a complaint as no one at American Express is willing to look into this matter further and assist me. I am especially disappointed because I have been their loyal customer for over XXXX years, yet every one of them refused to believe me. No one was willing to acknowledge the mistake on their end and provide me with a remedy for this unfortunate situation. I feel cheated and taken advantage of with the way the representatives went about handling this dispute.