Telkom still billing me nine months after acknowledging my cancellation request

I've been trying to cancel a data contract I have with Telkom since January this year. Telkom acknowledged my cancellation request on February 9th, and gave me a Case Ref. No. ********** 7.

In July I posted a complaint on HelloPeter saying that my contract had still not been cancelled. I received a reply from Telkom apologising and saying that the contract would be cancelled in August.

It's now September and I am still getting invoices and being billed by Telkom!!

I no longer live in South Africa, and am still being billed each month.

I honestly can't believe this. The Consumer Protection Act gives 20 business days as the time period needed for a consumer to cancel a contract - and Telkom drag it out for nine months and counting. They have acknowledged the cancellation request at least twice and told me the contract is cancelled, but then just keep on billing me. This is surely a massive Consumer Protection Act lawsuit waiting to happen?

What do I need to do to cancel this?