Chase Auto Finance loan payoff discrepancy Fort Worth Nationwide

In August, I traded my 2015 Acadia in for a 2016 Silverado.  The dealership contacted Chase for a payoff on the Acadia.  Chase gave them a payoff which included a payment I was not obliged to pay since I had traded the vehicle two months earlier.  Since the payment was automatically to be taken out of my bank account, it made my account short.  I called Chase and told them they had taken out the money from my account in error since I had traded the auto two months earlier.  The dealer paid Chase what they told them the payoff was.  Chase, according to their representative, took the payment out of my account anyway which made my account go intothe negative.  They said they gave the dealer a payoff which included a payment that I was not required to pay which made the payoff amount they gave the dealer be in error.  They would not refund my money and told me that it was my fault because I did not stop the automatic draft.  I had put a stop payment on the account for September, but they took it out in October,  though the account should have been closed as the dealer had paid them off. They (Chase) says that the payoff amount they gave the dealer assumed the September payment (really the October payment) would be paid. I do not understand how I am responsible for paying them an auto payment since I traded the car in August.  I intend to pursue legal means to get my payment back.