Telkom threatening to blacklist account after failed account cancellation

I cancelled my Telkom mobile account on the 9th of September 2017, which means including one month's notice my last debit should have come off for October. I have emails and documents to prove that this is the case.

Currently Telkom is requesting I pay up for December 2017 & January 2018. This means that Telkom owes me one debit order for the month of November but instead threatens to blacklist me if I do not pay up my account.

The agent on the chat line refused to assist and simply told me to pay up my account and that there was no other option after which I was thrown out of the chat.

I'm tired of calling various different department because no one wants to be responsible. Telkom failed to cancel my account and now tries to tell me that I was still using the account.

This sounds ********** to me.