Billing Fault on Telkom's side

Telkom wants to bill me over R800 out of now where after I have NEVER skipped monthly payments! This is obviously a billing fault on their side, but they won't even bother looking into it! They suspended my account, and now I can't even cancel! I escalated it to the Telecommunications Ombudsman (ICASA), and they can't even manage to get feedback from Telkom. Never will I sign up for any service with Telkom again! I deeply regret it!