Massive hike in contract fees

When you enter into a contract with someone, you expect both sides to adhere to it. If one party breaks a contract, you have the option to get out of the contract. After much deliberations I took out a contract in December. Previously I used a prepaid account. On Monday I was one of many clients receiving a sms informing a massive price hike. Is there a chance to get out of this contract? Vodacom claims that increasing the subscription is part of the very small print Terms and Conditions, which is very easy to hide behind. Why not announce the price hike and then give an option to leave the contract? Is it not *******?