CAR INSTALLMENT IS INCREASING ON MONTHLY BASIS

I am driving a car that is financed by ABSA bank for the past 5 years now, which I signed a monthly payment of R3200 from the day of purchase plus R85 for shortfall insurance, but now my frustration is that my installment is increasing on monthly basis, as now my installment is R3900, I then spoke to a friendly lady from ABSA who explained to me that there were some adjustment that was done on my account without my knowledge, she explain that: Balloon payment is removed, Service fee removed, and the car payment term was shortened with resulted my installment of go up but she was not certain at that stage is that is the problem, and now the term to finish the car is 2019 Dec and no longer 2020 Dec, so every time I phone customer service they keep telling me the matter is being escalated, this is my reference number:***7, my frustration now is that I am having arrears on my car and I was paying R4000 to cover them, but now that the installment kept on increasing I cant seen to make any difference to those arrears in my account.

Kindly assist with this matter.