Product: Credit card or prepaid card

I believe I've been a Discover customer for more than 30 years. Discover has a history of aggressively promoting 0 % or low rate balance transfers to me. I accepted many of them solely to take advantage of LOW interest rates. I have no recollection of ever knowingly accepting a cash advance ... which tends to have HIGH fees and interest rates ( which would be the exact opposite of my intentions with balance transfers ). All factors otherwise being equal, I wouldn't knowingly agree to allowing a high interest rate cash advance to remain outstanding for an extended time as I have multiple available credit facilities with low interest rates. On or about XX/XX/XXXX ( during the Covid epidemic ), I accepted the terms of a Discover balance transfer promotion by visiting the website and providing balance transfer details for {$990.00}. I believe it was my intention to transfer the balance of my XXXX XXXX XXXX  that is otherwise paid from my XXXX checking account. As I have told Discover numerous times, I don't recall ever seeing any notification of a cash advance being marketed nor do I recall ever seeing XXXX XXXX XXXXXXXX or disclosure information regarding a cash advance ... which would have been a warning sign to me that I was applying for the wrong product. I notified Discover more than 10 times ( and advised more than 20 staff ) that the balance transfer was mistakenly categorised as a cash advance. Discover recurrently acknowledged my complaint, said it was being investigated and temporary credits were being issued. I assumed this meant the matter was resolved and the balance transfer was duly recorded. Years later, Discover has said a number of troubling or conflicting things, ie the balance transfer ( accruing interest at 28.99 % ) was a promotion that expired ( despite no notification to me on application ) and is therefore a cash advance, the balance transfer destination invalidated the promotion offer ( despite no notification to me ), the temporary credits were not an indication the matter was resolved ( despite no timely notification to the contrary ), my payments over the past few years have been applied to the lower interest rate balance on my account and not the higher interest rate balance transfer / cash advance, there is no record of my application for the balance transfer promotion, I didn't apply for a financial product, Discover staff don't know if it's regulated or by which agency, there is no further internal appeal process, there is no Compliance department I can speak with, there is no external regulator I can contact for assistance, etc. Never has a Discover staff member offered me the opportunity to pay-off the Balance Transfer / Cash Advance and reverse the penalty interest charges, During a recent call, the Discover staff member seemed confused about how to do this. XXXX XXXX, I contacted Discover XX/XX/XXXX, XX/XX/XXXX, XX/XX/XXXX, XX/XX/XXXX and XX/XX/XXXX. I believe Discover has no idea what promotion they offered me and I applied for ( including associated XXXX XXXX XXXX and disclosures ). Moreover, they seem to have a predatory attitude towards the apparent lack of transparency when enticing me to benefit from a low interest rate when I fact I received an exceptionally high interest rate for the same advance amount to the same institution. Additionally, the apparent lack of accountability of customer support and supervisory staff requires me to recurrently call and check on the progress of my complaint... while Discover continues to earn above market returns that are not reflective of the promoted offer. Given the volume of my contact points, I can only assume this is intentional or negligently unintentional. Lastly, Discover customer support and supervisory staff seem to have no idea that they are regulated.