New phone contract but the phone is Junk

I have not received any feedback from Vodacom except that a consultant will contact you. Up to date I'm still waiting. The phone came back and it's doing the same thing, it freezes now and than, go off and you can't hear when some phone you . I don't know cause like I say It's now almost 3 months and I must pay for a phone that's doing this. I said in my first review they can cancel this contract because I can't pay for 3 years and sit with this problem.