Telkom billing department sucks

Telkom billing department is the worst. They created invoices before their system update the payment then they bill the customer incorrectly. I asked them to give me a new statement because I won't pay what I've already paid because their system took time to update. I was told they won't be able to create an updated correctly statement. I'm suppose to pay R538 according to their un updated statement I'm suppose to pay R1300. I won't pay what is not due to me.