Rude agent trying to force me into more expensive contract package

An agent phoned me to tell me the current pacckage I am on (24 month contract) is not avaialble from 1 January. She offered other packages but they are on average R150 per month more, when I said I do not want to pay more she got rude and said but I have to as there is nothing else. I just said I prefer to cancel my contract and she said then just pay the canellaton fee on which I reply I cannot be required to pay it as Vodacom is in breach of our contract if they do not offer the package I signed up for. She then trhough the phone down in my ear. I tried to get Vodacom to phone me again after this expereince via FB messenger but still no call just messages asking me all types of questions, with no explanation of what is going on.