Contract ***** !!!

I am a Vodacom Prepaid client. I lost my phone over the weekend and tried to do a sim swop on Saturday 7 March. The operator at Vodacom customer care informed me that i have a "contract" with RMCS and must phone them to do a sim swop. I have never ever had a contract with RMCS and when i phoned them they informed me that i must visit a vodacom outlet to get a new contract sim card ? How can i get a contract sim card when i am on prepaid ? This is totally unecceptable and i want some answers about this so called "contract". Luckily for the new consumer act i would be able to sue for inconvenience....and that will include Vodacom and RMCS. These 2 companies are working together and i can smell a rat !!