Coj postpaid to prepaid incompetence

I went to the coj office in Roodepoort paid the fee to be converted to prepaid as I have solar and I was only using around R200 in electric and getting a R1000 service fee. On the 1st of June the prepaid meter was installed. From then on post paid electricity should not be on my coj but it wasn't remove and infact it now reflects a massive increase in power consumption from 60-70 kwh to 500-****wh. I went back to Roodepoort and got told don't worry they will correct it by next invoice. No they didn't I called and was told again it will be correct by next invoice again it is still not corrected. 3 months iv been on prepaid and twice iv been told they will correct it and twice they have sent people to inspect and confirm I'm on prepaid. And yet 90+ days later still not resolved.