Removal of balloon price on my statement and updating my balance correctly

I'm having a problem with MFC division of Nedbank.im having a car finance with this Nedbank and I took the account 2019.I paid the deposit contract of R50000..the account didn't have a balloon price and it was a 90month contract today I'm calling nedbank n I'm telling them to fixed my outstanding balance and remove this balloon balance and I'm being told no the contract they have it says that and I'm telling the lady to send the contract and she says she sent it of which she didn't and I asked to speak to a manager since she's not willing to assist me n she thinks my call was a joke so to cut the story short please assist with removing this balloon price on my account and fix my term remaining