Incorrect billing

I have been having a billing issue and made them aware in February after realising that they have not debited like they promised Dec and Jan. Then in Feb I'm told I'm owing R4000+ till today that has not been rectified I'm being told that they still allocating my payments. I acknowledged the non paid months but they don't add up to R4000. A consultant assisted me last week and corrected it and sent proof of what I have paid to my surprise still today those funds are not allocated.