Business ProfileforU.S. Employees Credit Union

My vehicle was refinanced by U.S. employees credit union and I agreed on contract to a payment plan for every payday (biweekly), so for the payments due this month, I had payments on Sept 2 and Sept 16, 2022, which I made those payments but they were made after the assigned due dates, which I made them on Sept 6 and Sept 19, 2022 for both those payments. My next payment is due on Sept 30, 2022, which to my understanding is that if I make 3 payments for this month because I get paid 3 times this month, than I have fulfilled my agreement of payments for this month. The bank (U.S. employees credit union) is trying to convince me that once I missed the payment on it's due date than that means I missed that payment and will be behind on the 2 week period bill cycle and their computer system will than put me in a delinquent status to make another payment, even though I made the payment a few days later. I don't understand their billing cycle strategy and they are not explaining to me what my days late payments apply to, if it don't apply to that payment that I was late for. My understanding is that I am to pay them 3 payments this month in the amount of $211.25 and that's it, but their trying to make me pay another payment instantly after being a few days late for the previous payment. And a representative by the name of ****, have take money from my checking account 3 times on different occasions for this misunderstanding and when I confront her over the phone about the unprofessional act of taking money from my account without notifying me, there's an argument between the both of us and no resolution. I asked her to speak with her manager whose name is ********************* and the repre. **** tells me that she has spoken to ***** about the situation and I don't have a reason to speak with her, so I tell **** that I need to speak to ***** on my own account and I don't need her to speak for me. So, at this point its getting insulting and feeling like a regret of business.