I WANT MY REFUND FROM MFC Vehicle Finance

I am very disappointed with MFC, my vehicle account was settled in full and closed, I even have a paid letter. However they still took a debit order from account and freakin' irate because now they giving me a run around regarding the refund of the amount they debited. It has been 3 weeks now, and I am exhausted of calling in to find out when I will receive the refund and I am being told about 5 to 10 days working. I mean i have bills to pay, now I am late and receiving SMS's of unpaids because they not willing to pay the refund. This is lesson of not buying a car on finance, I will not recommend MFC ever.