Vodacom owes me money

I called Vodacom on the 2nd of Nov(I have the reference number) to cancel two of my contracts that were due to expire end of December 2020. Mid December I called again to confirm if both contracts were cancelled, to my surprise one was not cancelled, I then asked for it to be processed. Fast forward to January, I get an invoice consisting of both contracts. The cancellation was not processed for both, I’m now told that I have to pay even though I had submitted a notice for a cancellation . This is not the first time I experience something like this with vodacom and I hate that one has to go through so much hassle to get anything done.