Telkom bad customer service

I have contacted their callcentre numerous times about an account that was paid up more than 3 years ago.But according to the Experian credit bureau I am blacklisted on the system because of this Telkom account.Now I cant even apply for "Home finance" due to this.I escalated a few times to speak to a manager but they refuse to get a manager on the phone.I am waiting 4 months now to get this account that was never suppose to show up on as blacklisted off my name.Their customer service is pathetic:(