My horrible experience with Telkom mobile SA

What a horrible experience with Telkom mobile!!! I have taken a 24 month cellphone contract with Telkom over two years ago. I paid for my contract until the very last month and I also called them to request to cancel my contract. Unfortunately I was debited the following month and I followed up on that and I was told that I cancelled my contract late and they had already charged me for the next month. I understood that and I was okay with it and I also asked if my contract was cancelled and the person who was assisting me confirmed that my contract was cancelled. For about 3 or 4 months they stopped debuting and only for them to start again last month and this month. I tried to call them to enquire about the debit order but they are not picking up and I was referred to this self service system that I don't even know how it works!! I tried to call them several times but unfortunately I cannot reach them because they are cutting the call and refer me to a self service system before I can even speak to a consultant. I decided to reverse their debit orders with the hope that they will call me and find out what is going on. To my surprise just this morning, instead of calling me to find out, they referred my name to debt collectors claiming I owe them and that I should pay Telkom and then cancel my contract which is something I have already done a long time ago