Quick to debit slow to return your money

I instructed MFC multiple times to move my Debit Order date due to my salary date changing and this was not done resulting in my debit order bouncing. I instructed MFC that they could debit the outstanding amount and after 2 days they did not do it so I payed the outstanding amount via EFT. Even though I was called and informed them that I made the payment they still continued to debit amount resulting in me paying twice for my car this month. I have sent them multiple emails regarding reversing the debit payment even including the statements with both payments on them however they stopped replying and i am still waiting for my money to be payed back. It has been 2 weeks now and still no progress. I would rather not have a car than finance my next vehicle through MFC.