vodacom service sucks

hi, in December a vodacom consultant called me and offered me a new data contract she told me my existing contract is no longer valid, i only took the top up data, since then vodacom has been charging me for a device i have never received or asked for. i have been contacting vodacom for a refund and for them to sort this out with no joy from vodacom. disgusting service and a bunch of idiots