Mazda Wayne Management keeps lying while holding down payment money weeks after the car deal was canceled Wayne, New Jersey

Wayne Mazda auto dealer has offered me a trade-in deal which I accepted and gave down payment. A few days later at the signing day, finance realized that there was a major mistake and the deal was short by a few thousands of dollars (a miscommunication between sales and finance) therefore, they decided to cancel the deal (arguing with me that whatever sales told or offered me does not count). Now, a month later they are still holding my down payment money with all sort of excuses related to internal errors. Numerous Calls to management and finance have been answered by receptionist only delivering a message that "it has been taking care of and I should get my money back soon". I called Mazda USA which has been supportive BUT cannot help.