KEEPS ON DEBITING WHEN CONTRACT WAS CANCELLED

I had a contract with Telkom mobile that was suppose to stop end of April. I went the end of February to the Branch in Menlin to give in the cancellation form. The person that helped me that day did put in a query to stop the contract at the end of April and gave me a case number of ***9.Middle of June I got another statement telling me I owe money, when I called the call centre a rude and lady answer that could not tell me why the contract was not cancelled, instead according to her I'm behind on payments. Which I told her it is not possible as Telkom deducted it with debit order, then the case number are not valid. End of that month the debit did go off. The next month I got another statement with a bigger balance, I called again first the phone was put hold for half an hour, I hang up and called again where the lady told me again the case number are not valid because they could not get hold off me, which is bull **** as no one called me, she gave me another case number ***3 and took my number, but still they deducted so I reversed both that deductions. Got yet another bill. WHEN WILL SOMEONE GET OFF HIS ASS AND DO THEIR JOB. OR ARE THIS GAME GOING TO GO ON!!!