Still Billing me 6 months after buisness closed and moved

I cancelled my Telkom account in 12 May 2017. - the Hospital I worked at had moved and I would be relocating. - ( I had no equipment of Telkoms) - my number was ********** 759. This was done in writing - Telkom forms and e-mail. (receipt no ********** ********** 32011) I even over paid the account by R64 just to make sure - and it was sent to ********** I copied a 3rd person into the "final posting" - it is all documented but no !! Telkom kept debiting me, I asked my bank to reverse the debit, but two months later Telkom was able to get their debit order started again How do I extricate my self from what seems like sad situation? It seems like a terrible waste of time and good energy to take the matter to the courts of South Africa, prehaps there is an alternative way?