Constantly being billed for cancelled contract

My cell phone no. is ********** 150. One of the contract i had ended for the laptop and I cancelled it in May 2017 and same time sim card was disconnected. After two months Telkom debited me for R60.94 on the 21st July 2017. I dont understand because I cancelled by contract already. The next day I returned the debit order unpaid " with answer no authority to debit". On the 31st of July 2017 Telkom debited me with charges amounting to R115 fees for unpaid debit order I queried this with my Bank and was unable to reverse it. On the 6th of August 2017 I went to Cresta Branch where I opened my account/ contract to report this incident. The consultant phoned their Customer Care and they took my number to call back. They call me back same day about 13:00 pm and the consultant checked and could not find the debited amount for R60.94 and charges for R115 and he couldn't find anything and he requested me to e-mail statement showing these debits. On the 7th August 2017 I e-mailed statement to ********** and on e-mail address ********** and nobody contacted me. On the 17th August 2017 Telkom again debited my account with charges amounting to R115 I don't know for what now and this could not be reversed again. I still want Telkom to explain to me why they debited my account after 2 months of contract being cancelled.

This is inconveniencing me and these charges are costing me money and i need Telkom to immediately reverse these charges and explain why it was done.