no response from my emails sent!

my water bill was on average around R4000 per month and yet i recently received a bill for over R100,000 for a month - no leaks ( I even had 2 x plumbers to confirm this) I have sent many emails to Silumanzi Nelspruit and messages on the web site but little or no response - just SMS stating I am overdue payment of the massive bill. I can see that there is a problem with the actual accounting as the figures iI am sent on SMS on reading differ from what is on statements No response is very bad and i am very frustrated