HTC Hd2 — Refusal to exchange

I purchased my HTC HD 2 from MTN on contract on the 12/06/2010. On the 21/06/2010 I had to return the handset as it completely bombed out and refused to function at all. The Dealer (MTN) informed that it was due to a factory fault on HTC's part and sent it for repairs. The handset has now been in for 4 weeks and they cannot give me a date as to when i will be receiving it back (this after i was initially told 2-3 weeks!). i have argued with both MTN and HTC stating that I want the phone exchanged (I checked the warranty and am given this option) seeing as the handset was merely two weeks old! I also argued that I refuse to pay for a new handset but must live with a "repaired" one! They refuse to exchange and insist on repairing. I've made it clear that it is ridiculously pathetic from both parties to deliver such repulsing customer care! As a admirer of the product and an MTN client for over 8 years now I am disgusted to call myself one of their clients! This is by far the WORST service i have EVER received!!! I will be moving my contract to Vodacom and going back to my trusted Sony Erricson brand, something reliable!