Dispute on account

Phone Autopage Thabazimbi to complaint bout a invoice for the period of 2015/07/17 - 2015/08/16. They have invoiced me usage charges for the amount of R2915.26 which we did not use. I asked them for a itimised bill for that period but according to them they can not find one. How is it possible that they charge me but dont even have prove. I have send several e mails and phone calls with no reply.<br> Reference number: 784874