Telkom debiting contract fees after cancelling contract???

I have been struggling for months to cancel a contract with Telkom of which I haven't been able to use the service for years now. After posting my struggle with cancellation here I received an email telling me the contract was cancelled. However, they sent me a new invoice for a CONTRACT THAT WAS CANCELLED!!!!! I do not have an income currently and they just keep on trying to debit the amount up to 3 times per month running up penalty fees on my bank account as there aren't any funds in it. This *****ing should stop now!