Hiding behind small print to increase contract costs

I have had Vodacom contract for nearly 20 years. I changed to a new contact in January this year and my contract fee was R378.50. It in increased slightly with the VAT increase on 1 April, but them it jumped to R428.58 per month. As I pay per debit order, I only noticed this recently when I looked into my cellphone account. I contacted them and queried it, only to be told that the contract has a clause which states that they can increase the costs and you are bound by that, or you can terminate your contract. I don't know what the impact would be of terminating the contract, but to hide behind the fact that it is a clause in the agreement (which was never pointed out to me when I took out the contract) is a poor show. I am really angry at this level of deception - because that is what it is - hiding behind a clause in a contract that has so much fine print that its almost impossible to read.