Does anyone know how to post an official complaint to Apple?

My newly arrived Iphone 5 about 3 days old and costs around $1000 has to be replaced with a refurbished Iphone 5.

Here is the story:

I was looking forward to Iphone 5 and pre-ordered it and waited for about 3 weeks. It arrived on Friday the 12th of October, i was really excited about it.

After playing around for about 2 days, i have found that my silent/mute button is not working as expected, the switch seems to be loose and keeps toggling on and off. After browsing around the web, i've found that this issue is commonly found with the new Iphone 5.

Heres what it looks like exactly: http://www.youtube.com/watch?v=mGECFTPPZw4

So, i decided to book an appointment with my local Apple Store (Sydney, Australia). When i got there, they told me that my Iphone 5 can be replaced. I was expecting it to be replaced by a new one but they offered me a refurbished one. I was going to exchange it (reluctantly), but after giving it a closer look, this refurbished iphone5 seems to be a 'reject' product, since the color of the SIM card tray (white-ish grey) doesn't match with the black iodised aluminum frame. The difference is noticeable (i compared it with my faulty Iphone 5), so i declined it.

I would like to return it if possible rather than getting it replaced with a 'refurbished' one, but im not sure how to refund it since i bought it from Optus Mobile Contract.

I am very disappointed with the inconsistency in the Apple warranty, last time i bought an Apple Macbook Pro Retina (2 months old) and had some issue (No bolt attached to the SSD tray) and they replaced it with a new box. Im not sure why i can't do the same with my faulty Iphone 5 (3 days old).