BAD SERVICE,POOR INTERGRITY/TRANSPARENCY

I have been renting a flat through Just Letting Uitenhage for almost a year now,the block consists of 12 units owned by one landlord who leases them through Just Letting.Just letting send me a monthly waterbill where they use a R33.72 tarrif.I have since consulted the municipality for the applicable water tarrifs and was issuued with a tariff register that shows that the applicable is R15.81.I have communicated this discrepancy with Just Letting and requested justification of the higher tariff by way of legal municipal documentation to which they have blaitantly refused.All I need is clarity on the discrepancy but am not afforded such,,,,,,why should I pay for something I dont understand.I have even told them that as soon as they make me understand this variance then I will pay but they still refuse.I m not a troublemaker I am just a simple person who makes an honest living and am more than happy to pay if these costs are validated all am requesting is clarity on my enquiry and to date I havent been given any documents by just letting to validate their tariff.