Different balances given every time

I have been paying my identity account via debit order for over a year now and was told in april I ve 1 last balance of R108 to pay, so I paid that amount via debit order after a month I called in asking for a settlement letter and was told there is stil a balance of R270!! I was furious because if I knew there was more 2 pay I would ve settled it then, but I had to pay the R270 again end of june! On the 7th july I called in again to ask for the settlement letter and was told it would take 7-14 working days to get and they still confirmed my email address! Today the 21st july I called again to confirm when I will be gettin the letter and again I was told there is a balance of R20 still on the account!!! This is so unbelievable and unprofessional, how can so many people get a balance wrong and not contact you! I need someone to sort this out immediately, I will not be payin another cent on this account! I am diisgusted with tis company!