Telkom not able to finalize cancellation after sufficient notice and last payment made

I have given notice to cancel Telkom account in December 2017.

After following up a few times, it was indicated that the cancellation has been received. Telkom keeps on sending bills for periods after March 2018 after they have indicated that the last payment will be due in February 2018. That account has been paid. Unfortunately, after 3 months there is still invoices being issued.

Now a dispute needs to be logged.

After jumping through all the necessary hoops and procedures, Telkom can still not finalize this cancellation.