Vodacom unable to effect contract cancellation

On 4 December 2020 I renewed 2 contracts and cancelled 1. I was told that would be effected within a month. To date the contract is still continuing and they are charging me at twice the amount I was originally contracted for. I have called three times in the last two months to stop the contract and get refunded. I have sent two messages to customer care and no one has bothered to call me back. Today I called and I was told to send an email to retentions/cancellations. They are very quick to renew contracts but seem unable to do a simple cancellation. I need my refund, otherwise I am cancelling all my other contracts prematurely.