Vodacom keeping customers hostage

I had a 24 month contract with Vodacom for a tablet. After the two years, I continued for a few months on a month to month basis. I then decided to cancel it because I do not use the tablet anymore. Then the nightmare began. I went to Vodacom in Nylstroom to cancel the service. It was never been done. Then I received messages to say I am in arrears. I made a payment for the full amount in arrears today and asked at the shop in Hatfield that the contract must be cancelled. They gave me the number ********** . I specifically ask if I can call from a Telkom number because I do not have a Vodacom number. She said I can. I called the number and it didn't go through. I called the number of the lady that called me about the arrears amount ( ********** 222). In the first place the background noise on her side was so bad that I struggled to hear her. She just keep on telling me I must call ********** from a Vodacome line to cancel. If I don't have a Vodacom number, I must ask to use the phone of someone who have a Vodacom number. If I don't know anyone, I must buy a Vodacom sim card and call from that number. How ridiculous can this be. I still couldn't manage to cancel this and I refuse to pay any cent further. This is also the last straw and I will never, ever do business with Vodacom again.