Wrong company to do business with????

You would think if you sign a contract with Vodacom they will keep up with their side of the deal. I signed for 24 months at a certain price. But Vodacom can when ever they want increase your subscription one sided without giving you more benefits. If I sign a contract for 24 months I keep to it. I did log a complain with their call centre, and was advised that I would be contacted with in 24 hours. 10 days later nothing yet. I checked my contract and I did not even signed their T&C what they are talking about. Surely Vodacom can not treat their customers like that. I think this is a bully tactic that they are using. I have asked for the contract where I signed. Nobody calls you, nobody follow up and nobody have an idea what is happening at the moment. I think I should change the contract one sided and only pay half the subscription, and see how happy they are. I refuse to pay more for my 24 month contract than I have agreed to. If not I would like to cancel my contract. This is the last time that I would have a Vodacom contract on my name.