Vodacom - Poor service and lack of information

Vodacom switched me over to a "sim-only" contract without telling me that this triggers a new 2 year contract period and I subsequently can't do an upgrade and obtain a new phone until 2019! I'm so sick of the service that Vodacom provide, they think that because there aren't many service providers to choose from in South Africa that they can just treat customers unfairly.