I had paid up my account with you guys, how then do you take my contact details to another company without my consent

When I called Vodacom my number from Prepaid was just moved over from RMCS to contract of R65 airtime per month, I have never ever signed a contract or requested a contract ever from these people now suddenly can't do a simwap because I have a contract with you. I want my number back immediately. I want my phone number **********). Me losing my phone was a wake up call I need to check my accounts with creditors something.