MFC - a big let down!

I have been liaising with a person Rosy Joseph who will not listen to me or admit that she is mistaken with my settlement on my vehicle which has already been paid by insurance. I have done the figures and proven everything. She is now trying to make me pay more by sending a new settlement figure and is blocking my application for another vehicle. There is no supervisor or senior person to talk to - their service to date has been awful and totally unacceptable - how come she can make decisions on whether I buy another vehicle and who gives her this authority. I will simply go to another finance house who is more client friendly. This is shocking - we wont bank with Nedbank now.