Product: Vehicle loan or lease

I changed my checking account to a new bank in XXXXXXXX XXXX and changed my auto debit on Bank of America 's website to bill the new bank for my auto loan payments. Bank of America has a verification process for the new bank, which I completed and I got an email from BoA that I could now make the change, which I did. 
My payments are due on the XXXX, so my auto debit has always been set for that day. XX/XX/XXXX would have been my next payment, but the payment was taken from my old bank ( with no money in it as I was in the process of closing it ) on that day. The same amount was also showing up in my new bank to be paid on XX/XX/XXXX. The details for my new bank were accurate and included routing numbers as well as the name on the account reflecting the exact name used on BoA ( and not on my new checking account ). This information could only have come to my new bank from BoA. 
However, when I called BoA about the double dipping, they have records only of the mistaken payment from my old bank. I advised them this was incorrect, and I reversed that payment through my old bank. It is time for me to make my next payment, but the correct XXXX payment is still showing as paid from my new bank, while BoA can't locate the payment on their side. 
I have called numerous times, been through hours of rerouting into numbers that can't help me, supposed transfers that put me back to the main screen ( push 1 for ... ), and information that was contradicted in subsequent calls or by facts. Now, BoA is sending me emails and a letter about my past due account, I have been charged a late fee, I've been told everything from we have no record of your payment to we found your payment so we mailed you a refund check! A refund check for a payment on my account makes no sense at all, and it didn't arrive anyway. I was told it was mailed on XX/XX/XXXX, they have verified my address, yet I have not received a check as of XX/XX/XXXX. They have never sent me any information about this check and only one person said it was sent. Everyone else has said they never got my payment. Even if they had mailed it, that would be wrong as it would require me now to cash the check and send the funds again, while they could keep the late fee and additional interest because I " paid it late ''. Meantime I've had no access to those funds because they were with BoA or in limbo in a check ( which I still haven't had them verify they even sent ) while my account gets charged and I'm now directed to the collections number. However, the branch manager at my local BoA told me that this is common practice with BoA. 
I went to a branch office on XX/XX/XXXX, to be told by a woman they said was a manager ( although she had no office ) that they can't help me as they have no access to my account since auto loans are a different area. 
Although I initially believed they are incredibly incompetent and have very poor customer service, I now feel due to all the lies and issues that this is intentional. I am being harrassed now for a payment I can prove I made. I can prove they received it. I can't find anyone who understands and cares. Meantime I am being charged interest, a late fee, and I don't know how I can trust future payments will be correctly applied. They have my money and have had it since XX/XX/XXXX, but they truly don't seem to care.