Complaint sub-issue: Credit card company isn't resolving a dispute about a purchase on your statement

I have attempted to establish an automatic payment allocation request in order to pay on my revolving account and then excess to be applied towards my promotional balance. Despite numerous efforts and various individuals on-line and via phone I never could get a clear response on whether I could establish this request, which by the way this language ( automatic payment allocation request ) was provided to me by the credit card company ( Department Stores National Bank ) associate via email on XX/XX/2019 @ XXXX. Despite my efforts I realized that the only way to ensure I could make payments on my promotional balance was to make a one-time payment after my monthly auto payment posted. So on XX/XX/XXXX @ XXXX I called and spoke with a gentleman who during the conversation stated he COULD set up the automatic payment allocation request ( according to website the conversations are taped ). So I made my one-time payment ( {$530.00} ) towards my promotional balance and my {$300.00} auto payment had already been processed since it is an auto payment, but the statement was not available until XX/XX/XXXX for me to know what Macy 's had done. Previous months my auto payments were in the amount of {$400.00} and always had been applied towards the revolving credit and outstanding balances, per Macy 's policy that monies are applied to revolving and outstanding balances. Anyway I requested, because this associate said he could it for me to set up an auto payment of {$800.00} for the following month ( XX/XX/2019 ) and out of that {$800.00} I would have {$300.00} applied to the revolving and outstanding balances ( which exceeds the minimum amount due ) and {$500.00} towards my promotional balance. I requested some type of confirmation from him after I made this arrangement and I was told he could not provide such a document at that time. I then received notification on XX/XX/XXXX I had a message from Macy 's and noticed the letter stated auto payment of {$300.00}. I then realized there was an error. I called and spoke with someone who then told me no such auto payment allocation request program exists, despite me being told via phone and email that it did. I then clarified that the {$300.00} was only to be applied to revolving credit and outstanding balance and I would then pay the additional amount each month to pay on my promotional balance. I then received my statement on XX/XX/XXXX and realized that they had applied my {$300.00} auto payment partially to my promotional balance instead of being applied to the revolving credit and outstanding balance. The odd thing about all this is that I knew that I had to wait till my auto payment posted, which I could see on the website it had by the XXXX of XXXX. I waited purposely for that posting so that when I made that one-time payment of {$530.00} that all of that would be applied to my promotional balance. Plus all of my previous auto payments have been applied to the revolving credit and outstanding balances ( which according to Macy 's is the process and expectation ). Due to the historical mis-communication issues I have had with Macy 's and the ongoing lack of consistency in receiving information from Macy 's I decided I would also email my request after I made that call on that letter I received about setting up auto payment of {$300.00}. I did so to ensure this issue would be documented and had the expectation the error would be corrected. But the email response I received brought me concern as it stated it would take 1-2 billing cycles to correct the problem. Which does not make any sense when they can debit my account within 24 hours but takes them 30-60 days to correct the problem. Due to the error on how the auto payment was  applied ( not completely to revolving and outstanding balances ) my interest accrued was higher. On my XX/XX/XXXX statement my minimum balance due for my XXXX payment was {$150.00}. I had an auto payment of {$300.00} and they applied only the minimum due ( {$150.00} ) and took the remaining of the {$300.00}, which was  {$140.00} and applied to my promotional balance. I had already made a one time payment of {$530.00} for that balance that is why I wanted the {$300.00} towards my interest accruing balances, which is what they have done since I set up auto pay. In my May statement they applied {$7.00} to higher interest ( 27.49 % ) to the balance of {$120.00} charging interest accrued of {$2.00} leaving a balance of {$110.00}. The remaining of the minimum due which was {$150.00} was applied to the lower interest ( 26.75 % ) to the balance of {$2900.00} charging interest accrued of {$67.00} leaving balance owed of {$2800.00}. So if they had applied the payment correctly an additional {$140.00} would have been applied and I would have had a lower balance and less interest accrued. Actually if you review how they apply my payments that {$140.00} would have paid off that balance of {$120.00} because typically they apply $ XXXX {$150.00} to the other account each month. When I inquired to Macy 's on the issue and concern about correcting the interest accrued once they apply the monies correctly they would not respond to that question specifically. I have sent 4 emails demanding that answer. In lieu of their unethical and unreliable communication and business practices I fear they will not account for their mistake and I will not get the benefit I should have gotten without their mistake. Plus I asked them as well in those repeated emails to confirm that mistake would never occur because the evidence of what I said is in the tapes and reinforced with numerous emails. I also requested to be sent the credit card agreement on how they apply payments, basically their business practices in reference to how those practices directly affect me. They informed no such document exists. Now I find that highly unlikely when many individuals would like to read the fine print, but no fine print to review. How can that be legally allowable.