Tshwane water bill is a ****

My water bill ****.february bill was about R5000 and now October bill is R6000 .other months it is less than R2000. I went to the offices in Centurion in March and was told to check for any leaks which I can confirm there are no leaks.i feel that something is not right here because I don't have leakage .I am not working and I struggle to keep up with this please investigate