Not giving feedback, failing to do what was asked.

I don't have a problem with the people that helped me,but after I called a few times about cancelling of contracts and still they did not do what I asked,it has gotten to the point that it is irretating me.They are still charging me for a contract I cancelled.Everytime I call,they just tell me,they will call me back.They don't.I have been by Vodacom for a long time,but I have decided that after this,I will move my business to a other network as soon as my other contract's expires.