Signing us under FALSE PRETENCE/ DECEIVING US

I took a contract with people who introduced themselves as Vodacom who promised to give me airtime every month which happened from October 2015. I am not sure if they did not get money last month because then my number was blocked from 08/12/2015 till today. When I contacted Vodacom they told me it was not them who blocked my number but their trade partners(The Postpaid Co/ Rewardsco). I phoned that company and till now my phone is still blocked and that company(the postpaid co) are not helpful at all. I just need to know who blocked my phone and if I owe money how much must I pay before the phone is unblocked. I need to know the company I am contracted to because there is Postpaid company and Rewardsco.