Inability to cancel services and send correct bill

I gave 30 days notice to cancel my ADSL line (internet and phone line) on 1 June as I was moving house. Store staff in Cape Town CBD store told me to send the cancellation via email, which I did, and as a precaution I visited the Canal Walk store on 7 June to log my request in person. The following week I returned to the Canal Walk store to make sure my request would be actioned and was assured it would be cancelled on 1 July. On 15 July the line was still active so I returned to the Canal Walk store and asked the staff to cancel my line immediately. I was asked if I wanted to cancel everything - internet and phone and I confirmed this request. I paid my bill up tiIl 8 July and was told to wait for my final invoice, and to ignore all bills until I receive it. I returned to the Canal Walk store after receiving my bills for August and September to query why I was still being charged for services I wasn't using, and have been communicating with Telkom via facebook since the end of September, but they have still passed my bill over to an external debt collector. Ref ***7 was initiated to Credit Management on 30 October to be actioned within 7 working days, which was two days ago.