Contract Cancelation with Vodacom SA

I have a contract with Vodacom that i wanted to cancel since October 2023. When i call them at first they told me to wait until my contract end date which was in February 2024. I called Vodacom after that and everytime their Customer Service Agents realise that i want to cancel the contract and not upgrade they end the call, i have tried calling many times and they do the same thing. I decided to stop paying Vodacom amd wait for them to disconnect my contract and they have not cancelled it after 5 months of not paying them. They send threatening emails saying they will disconnect my contract in 7 days if no payment is made but its been more than 7 days since the first email and my contract is still active