dumb people

I've took a contract with vodacom and my contract with vodacom in 2008 if I'm not mistaken and it was a 2 year contract I've paid them well till my contract with them was over and their agency called me en told me my contract with vodacom was on en they will give me a phone for free to thank me for paying them well I was over the mood by that time the phone was delivered and my problem started money was debited from my account by vodacom and when I ask them they told me I have another contract with them and I owe them R800 it was in 2011 by then en I told them I don't owe them a cent and they must stop debiting on my account fair en fine they didn't debit after sometime I receive calls from their attorney telling me that I need to pay vodacom their money which I won't pay so please help me out with this problem cause they've putted me in credit berue over a stupid phone c3 just imagine I've took a blackberry 8520 for contract when I upgrade I take a c3 it doesn't make sense I'm very upset with vodacom please take this matter to their head office en I wanna hear from them here are my numbers *** thanks in advance