Telkom contract ended years ago but still charged to date!

My contract with Telkom ended years ago and they're still debit'ng my account to date! I've been trying to call but their Customer service line sucks, takes you through a million prompts then cuts you before you speak to an Agent! I've been trying to cancel this contract but I'm not winning! They've chaoed enough of my money for months without using the service! I've reversed the past x3 months debit orders but they still attempt to take my money nonetheless! I've sent emails and requested call backs cause one always struggles with direct calls! NO joy to date!!! I want this contract cancelled effective immediately! The reversal charges must be cancelled as well, for months I've been struggling to get through to cancellations! Telkom service sucks especially with cancellations, they can't force to retain me by ignoring my requests!