Cell C month to month contract

August last year my contract was due for upgrade but Cell C did not have any decent handsets. In November they phoned and advised me to take a month to month contract that I can cancel or upgrade at anytime. So last week i went to the shop and they had a S21 in stock and i wanted to upgrade. The consultant said that he cant help me as i am locked in a 24 month contract and need to pay R7000 to cancel or upgrade the contract. I never took out a 24 month contract, i never agreed to this. Consultant agreed and said the clauses of the contract changed. This without my knowledge. He said that there is nothing he can do about it. The consultants that answer the customer care line say they cant help me! The page on facebook keeps on saying they will get back to me! They still had a advert on the wall that states month to month but people are getting locked in a 24 month contract. Misrepresentation.