Cell c cancellations avoid customer to exit contract

I have been a loyal client to cell and have had a cellphone contact since 2013 and have been on month to month contract , I called their cancellation department on the 14/05/2020 and advised them that I would like to cancel the contract. The Consultant assisting me advised that I have to give them a months notice for the cancellation to be active , I then understood and proceeded with cancellation. Surprisingly I call this month to confirm on the cancellation and it was never submitted meaning I have to resubmit the cancellation again and be pay again for the next to month for a service I no longer use and need. I feel cheated with cell c cancellations. They making excuses and making it difficult for me to exit the contract