The noise sounds like this: https://www.youtube.com/watch?v=0OW9jFwngFw
The first thing I did was contact Xbox support and they gave me the choice of sending it to them but I figured I would take it back to Big W. There I was told that because it wasn't an actual problem they couldn't return it. Then I contacted Xbox support again and I can't remember what happened but I ended up at another Big W store and there I was told that they would send it to the manufacturers for repair and I would get it back in 6-8 weeks, so I figured I would do it myself. The next Xbox person told me that the unit I get from them is refurbished which I'm not totally happy about it since I've had this thing unpacked for 2 days.
The noise was something that occurred on a lot of systems a while ago called coil whine but a patch was supposed to fix it a while ago and coil whine isn't supposed to occur while playing a game, while my noise does. Also I wouldn't really have a problem with the noise since it doesn't really affect anything (though it is annoying) but there were some posts on reddit where they had the same problem and their consoles died on them out of the blue. So is Big W correct in what they're doing? I assumed I would be entitled to a replacement or refund as the item is doing something it shouldn't be, though the defect doesn't affect the functionality of the console, yet it's not in the state that it should be. So should I push at Big W for a proper replacement or stick to a refurb unit?
I'd hammer BigW for a replacement given it is defective out of the box.
It is unfair to expect you to wait up to two months to get something you only bought two days ago.
Get a manager involved, post it on their Facebook while you're in store, cause a ruckus (but don't be belligerent).