Product: Credit card

I have an XXXX XXXX XXXX credit card with Chase. This card provides a feature called EPP ( Equal Pay Promo ) whereby when I buy items on XXXX over a minimum amount, there is an option to pay over an extended time ( XXXX  months, XXXX  months, XXXX  months ) at XXXX  % APR. 
I had taken a balance transfer offer from the card at XXXX  % XXXX until XX/XX/XXXX for which I am making the minimum payments every month. I was made to understand that if I made any new purchases after a balance transfer, those purchases would start accruing interest right away. So, I paid off all my new purchase balance to make sure no interest would be charged. I confirmed with Customer Care and paid a last amount of {$10.00} on XX/XX/XXXX whereby they confirmed after that no new purchase interest would be charged unless I made more new purchases. Further, I was told that there would be no interest charged if I made Equal Pay Promo purchases and paid the EPP monthly amounts in full till the promo lasted ( XX/XX/XXXX months ). I asked customer service multiple times to confirm that Equal Pay Promo purchases will not accrue any interest even when I had a balance transfer promo going on. After these multiple confirmations, I made sure that I only made EPP purchases on XXXX. No other new purchase outside of EPP has been made since then.

But I started seeing that I was being charged interest under the Purchases category every month. I called customer care and asked them which purchases were accruing interest since I had not made any purchases outside of EPP and EPP does not accrue interest. At this they could not give me any details of the purchases that were accruing interest, but the rep waived the small interest of ~ {$2.00} at that point.

But next month, again I saw interest charges coming back under purchase category even when I had made no purchase outside of EPP. So, I wrote a secure message to Chase on May 13the, 2024, asking for clarification. There were a few messages back and forth, but they failed to clarify the issue. They kept beating around the bush about balance transfers and new purchases but did not answer the actual question about how I was being charged interest on EPPs when EPPs dont accrue interest if paid off during the promo period.

Then I called customer service and talked to a supervisor this time. He kept me on hold for a long time and then came back and said he saw some purchases on his end that were not showing EPP even though on my side, every purchase shows as an EPP purchase on the credit card statement, and hence the interest was being charged. He said he would escalate this issue and the bank will send me a mail stating what they found.

Chase sent me a mail dated XX/XX/XXXX. In this letter they said that unfortunately they can not reverse the charge because they have determined the amount of interest is correct. They again did not give me any details of which purchases were accruing interest. 
I am extremely unhappy with this experience. Chase customer care is not giving the right information repeatedly and they are being completely non-transparent about the interest charges. I have had a similar bad experience with them late last year about a balance transfer and wrong information being provided to me multiple times, which I brought up with CFPB ( Complaint ID XXXX ) and Chase then got back to me and resolved the issue. But this seems to be a perpetual problem with them where they dont provide the right information, are not transparent, and are wrongly charging me interest. 

I would request CFPB to please look into this matter and help me get this resolved.