Still invoicing me over 2 months after cancelling!

In late November 2015, I wrote an official letter to CANCEL my Telkom business account and transfer ALL services to my father's name, as he was taking over the phone and internet lines as a residential client. He brought this letter into the Greenstone branch along with his application forms to sign up for the service. On 11 Dec I received an invoice for about 1/6 of the normal amount, so I guessed this was just the last payment for the outstanding amount before the account was CANCELLED. The amount was debited from my account and I went on with life. On 11 January I received a new invoice, for the \Home Uncap basic\" Data service, which I had clearly cancelled along with everything else. I wrote a new letter instructing Telkom to CANCEL my account, including the Home uncap basic, and to TRANSFER the service to my dad. On 14 January, he again brought this letter, along with the original one to the Greenstone branch, and the woman behind the counter told him \"I don't want to read, tell me what the letter says\". The letter in fact said that she should ensure the account is CANCELLED and NOT to charge me. Not only did the debit come off on 1 Feb, but today I received ANOTHER invoice!!"