incorrect water billing on my account

very poor service. been to their office a number of time but still not assisted. my account number *** is being incorrectly billed for water for over a year now. my unit is no. 18 and unit's 35 reading are billed on my account and its been over a year now. in August alone I was billed 39 units that's enough water to fill a vey big swimming pool. i have sent emails and their telephone at the office are not answered. do not know what to do anymore