Bad service from Telkom

I cancelled my services with Telkom in June 2020 due to the bad service I was receiving regarding a new Fibre installation that no one could sort out. The Fibre line never worked from day of installation. Despite cancelling and speaking to numerous agents, I was billed for Aug, Sept and Oct. I have written emails and made numerous calls with no resolution, I even escalated to TeamLeaders with no joy.