Vodacom abuses their contract clients

I am extremely disappointing with the ongoing poor service I receive from Vodacom. I have been trying for 4 days to do a sim swap and have been sent from store to store. I had requested they cancel my contract as this is shocking. I run a businesses and for 4 days was not able to make or receive calls. After being with the for over 25 years, in addition they tell me that all new contracts get a reduced rate for data, however the loyal clients must pay the full price. that was even more sickening to hear. It seems like they don't give a dam, as long as you have a contract they can take advantage of you all the time. I even moved to the most expensive contract to avoid these type of issues, still the same shocking poor service. What rights do I have as a consumer to cancel my contract if the service is of the poorest standard and move to another provider?