Johannesburg water

We were away for a month from home when we came back there was a water burst inside the property for that month it was apparent as the pipe burst from under the pavement. the water bill came to just around R100,000 no insurance would cover that and Johannesburg water said it was inside the property not their mistake. Any one have any experience or suggestions to try to get Johannesburg water to reduce that bill. Apparently the water was leaking underground for a while only saw the water when it pipe burst from underground and Johannesburg water never did a reading for months it could’ve been avoided if there was readings on a monthly basis. They just send and estimation for most of the year.