Contract Cancellation - Non Existent Service and NO feedbac****

I have had it with Cell C!!!! I cancelled by upgrade with Cell C on 5 November 2019, after Cell C signed me up in an incorrect upgrade contract on 1 November, after I specifically explained to the Sales Person what I needed and he insured me that the contract was the correct one. The new contract was due to start 11 November 2019. Since 5 November I have visited the Cell C Waterfall Campus store, I phoned numerous times, I send emails and cancellation letters to the store manager, area manger, retensions department and NO ONE is responding to me!!! I am sitting with an incorrect contract that I cancelled and with an unused cellphone that Cell C needs to collect from me!! I will not pay for a contract that I cancelled well within my rights within the consumer protection act due to Cell C's ignorance and negligence. Cell C's services is non-existent - I just receive no feedback whatsoever but Cell C can however phone me 10 time each day for an upgrade on my other number which I have cancelled as I will no longer be associated with such unprofessionalism en non-existent service! I have been a client of Cell C for many years and can honestly not believe that you can treat clients this way. Can someone at Cell C respond and sort this out or do I need to refer this matter to the consumer board?