Unreasonable Additional Charges

I am unsatisfied with procedures and services I got from the bank. I got a car through finance on the 2nd of May. The principal debt was R311 000, I requested a settlement letter from them on the 25th of May and the balance was R322 000, I called in to ask what the additional R11 000 was for, and their consultant said she doesn't know but that is the settlement amount I must pay.