Unathorised debit orders from Telkom

I had an account with Telekom which I closed and paid up all dues on 29.01.2019. I paid through one of their agents called Blake Collections. My account number was ********** 32612. However nd to my dismay and anger, Telkom continues to deduct money from my account almost every week. This borders on ***** and human rights abuse. Please help me stop Telkom from deducting my money. I no longer have a contract with them. Telkom issued me a Credit Management Delisting certificate on 11.02.2019.