Unable to cancel contract or get any progress on the matter

I have been phoning since 8th January 2025 to cancel a contract. Each time they confirm it is cancelled and the device will be collected and I will receive a refund. After making another 5 follow up calls as the above was not done still no collection. It is impossible to speak to them , as they constantly put the phone down in your ear , after being put through 3 times. I am completely lost and cannot get any form of resolution from Vodacom.