Unexplained charges on account.

My last statement said that my balance is R121.83 and my installment is R36. Today I went to the your Brooklyn store to pay my account I’m told my balance is R230 and that my installment is 197.71. How can the installment for a 6months plan be R197.71 when the balance is said to be R230? Your employees cannot explain to me the leap from R36 to R197.71 when I haven’t made any purchases. Please make sure to sort out my account so that I close it.