eThekwini Municiaplity water department

I am having a problem with water department within the eThekwini municipality. My monthly water bill for the past 9 years have always below 25kl which is always below R500 for both estimated and true readings. I have just received the February bill and it indicated that I have used 114kl for two months which is more than R4000. which is not possible since I have no water leaks within my premises. I have asked the municipality to provide the valid calibration certificate for the functionality of their meter and they say whatever that has been read by the meter is what I have consumed. I have asked the water department to send someone to investigate their device, they do not want to commit themselves. The worse part about them I was advised on Friday(28/02/2020) by the Pinetown Customer Service (Sizakala) that I can only email, phone or send WhatsApp but I cannot go physically to their department which is a bit odd. If they keep on dragging their feet, it will end up affecting current bill payment, because they can easily come to disconnect the services. Kindly assist for this matter to be resolved.