Unfair treatment and changing contract period

I am absolutely appalled with the utter lack of service and unprofessional manner Cell C is treating customers. I am under Debt review. When I wanted to upgrade they told me I can not anymore they changed their policy. Then a consultant called me and said I can upgrade but I have to take a data card of R300 pm with. That is the only way I can upgrade. I said Indid not want to do that becaues I do not want to pay an additional R300 pm. He informed me Injust have to keep it for 3 months the I can cancel I. I explicitly asked would I then be done with it and i do not have to pay the R300 any. He said yes. It is a month to month and I can cancel after 3 month. When I called Cell C after 3onths to cancel they informed e it was changed amd is no a 2 year contract. If I want to cancel i must pay the canacelation fee which is 50%. This was not what I was informed vy the consultant. I have sent numerous emails and made a lot of phone calls. They just say their T&C says they can change the contrat. I do not agree with this. Is it even legal to change my contract term without my concent and expectinge to pay for something I did not agree upon. They already deducted foe April (pro rata). I have been struggling to cancel since the beginning of March.