COJ Sewer charges at R45,747.00 for a single property!

I have been dealing with several City of Johannesburg accounts for our company. One of our Companies owns a property and the Sewer is charged on availability, these monthly charges is R45,474.00 per monthe, our water account is +/- R10,000 on average per month. COJ consultants does not have a clue as to how the Sewer billing should work and what charges should be raised. Several of our larger properties are charges are based on Stand size and the sewer charges is then R826.02 per month. I've complained and was told that it's because its a multi dwelling property and each dwelling on the stand is being charges R378.95 (there is 120 units), but according to their Tariffs this is for properties larger than 300m2 to 1000m2, and our dwellings is on average 104m2

I don't know if there is anyone in the council that will be able to assist with what the tariffs for sewers should be on Multi Dwelling properties.