Incorect Billing and Poor Service delivery

On the 2nd of November I received an sms saying I owe water and Sanitation an amount of -R401,I had no problem of paying it cz that what I pay everymonth.On the 3rd of November the following day I received another sms from Ismart saying I owe -R841.I spoke to Patrick Malanda in billing department on the 3rd of November and he promised to fix this before end of business the same day and He not.Today is the 11 that error still reflects in my account.Can you kindly fix this as soon as possible cz there is no way i will use water for that amount.What is that i do with that water?Fix this!