Abnormal water bill by ISMETERING

I am staying in one of huurkor properties with my 18 moths old baby and water and sanitation is managed by ISMETERING, in 2019 I was charged Water bill that amounted to R800 for three consecutive months and was told my flat could be having a leakage that I’m unaware of ,they came to fix ,now that I am moving out I got billed R1222 for water and sanitation,such amounts are paid by people who got pools in the yard not is a flat ,lodged a query last week ,still awaiting response.