Telkom refuses to cancel my contract in order to debit me

I have had a Telkom mobile contract for over 2 years, the contract term has ended in May 2018. I have called in Telkom customer services to cancel and move to prepaid as i do not want them to debit my account anymore. i am now frustrated as they are still debiting me. i called in the call centre 3 times and i have even been to the Telkom stores twice (Gateway and Phoenix Plaza branches respectively), Furthermore, my contract was for R108 per month and now Telkom is debiting me R202.70. This is ******* as Telkom is now being oblivious to my cancelation request in order to debit my account. i would like this account to be cancelled and my money to be refunded to me (from the time i issued Telkom with a cancellation request. I now understand that Telkom is beyond useless in anything that they do, the appauling service in all aspects of the business is terrible, i would just like to part ways with them, and they are not allowing me to. It is because of this disgusting service from Telkom, that i have moved my WiFi ADSL line to MWEB and canceled my landline. i just need to get this mobile contract over now, can you please help me ?

regards Faiyaz