Poor customer service and no care for existing customers

I am angry and frustrated towards Vodacom. I cancelled the contract within stipulated days of receiving the sim card but they went ahead and billed me. I had cancelled the contract more than once personally at the shop and also by logging a ticket telephonically. I called them also after realising that they marked my ticket as resolved without giving me feedback. I don’t want the additional contract because I cannot afford it. I did not renew the contract because of that and the consultant on the phone **** to me.