Bad administration

After I wrote my complain regarding the following amount debited R399.97 and also R61.97 a lady called yesterday and I asked her what is this amount for to my understanding I should only pay R169. She told me about a pro rata of R61.97,advance payment of R169 and current month R169 it gives a total of R399.97. It appears to me that I have paid pro rata twice because they have already debited the pro rata of R61.97 separately. Again debited R399. 97. One another issue is that since the date of installation to date I didn't receive a certificate. I told her that I didn't receive the certificate. This people must do thier calculation correctly.