Bad service.

I send my phone in under warranty. I couldn't hear any calls and on the other side they battled to hear me. There was a small dent on the phone and due to the dent they wouldn't even look at the phone! Fine I didn't really get it. I asked them to send the phone back. They rep**** about a week later and said not until I have paid the R330, now things are heating up so I say fine, to whom do I make this payment? No answer? I go into the MTN store where I sent it in and asked if I could pay for the phone to be released? They gave me all the correct details. I made payment about 12 days ago and am still awaiting the phone to be released in I think Cape Town. Can someone please help to speed this process up?