Vodacom *****ing from me

Vodacom started hounding me telephonically last October to upgrade my contract. They told me I would still be paying for the old device for two more months. I went into Cresta store in December to upgrade. I paid R150-00 to be assisted by a human, who assured me I no longer owed anything on the old device. At the end of December I was again charged for the old device. I tried and tried to phone the person at the store for an entire day, but was told I could not speak to her. She then emailed me to say there was one more month owing on the old device (December). Now at the end of January I have been charged again for the old device. I wrote to "Customer Care" (!) who told me to go back to the store. I rep**** that I would have to take a day's leave and pay about R200-00 for transport to do this. So much for "Care"!! So they will continue to ***** from me and there is no way to stop this. Disgraceful!