Taking tenants for a ride.

I don't normally do this but City Property is taking for a ride. They are telling me that in April I consumed 3 Kilolitre (3 000 liters) of water. Come May they say I consumed 21 Kilolitres (21 000 liters) of water and in June in I consumed 10 Kiloliter (10 000 liters). Bear in mind that the building had no water for 2 days for the May billing. The reading for May was an estimation that is later proved correct by the billing of June according to City property. How on earth do thus an individual consume 21 000 liters in the month of which two days there was no water? This is pure manipulation of the water system and de*****ing the customers.