Jet Accounts

Good day please assist me in the following I have always paid more than my installment with Jet and when I quered my settlement on my account they said that the total balance on my account is the balance as on my statement, I rep**** that it is impossible that my account balance and my settlement could be the same I then asked what my installment is and they rep**** that my Installment is R0. 00 and once again I rep**** that once installment cannot be R0. 00 the said that is how RCS accouts work and that I have to abide by that and pay my installments till the balance owed is settled. I have paid R600 once again at end of May 2022. My budget plans balance prior to payment was 12months = 961.54 and the 24months R323.37. I have not baught in the last year on this account. Please assist if possible