Incorrectly billed

I have 2 contracts with 8ta mobile (Telkom) since 2011, 2015 November my account was suspended because of incorrect billing.The total amount of the contract monthly was R 339, R200 for data contract and R139 for cell phone contract.No payment was made for November as I was incorrectly billed for an amount of R749 for an option I didn't choose.Since 2015 December up until 2016 February my account was suspended and I wasn't getting any services from 8ta and yet I was still being billed and invoiced, the current bill is R1800 I mean why bill if I am not getting any services from you. I have 3 cases logged and I have been contacting them several times but still no help. This is an issue that needs to be solved, I've been a loyal and a paying customer since 2011 and now this ******** ahg sort this out please