Same situation with me as well
W: 0000-0021
X: 0002-F001
Y: 00C2-03E0
Z: 0000-0000
Console had 3 rlod. sent it away for repair. came back yesterday and had no connection to xbox live. passed everything else and failed on xbox live.
Worked pefectly fine before i sent it away and now nothing. tested other consoles from friends. they worked fine no problems. So after two failed attempts at talking to live support i called tech support this morning. I explained the whole situation to her with it worked, sent for repair, now it doesn't. explained that other consoles worked fine connected through router and connected directly. mine does not work at all.
I kept re-inforcing that it worked before i sent it away and now it doesn't and other consoles do work. Also told her that i am not the only one experiencing this. so after an hour of re-inforcing my point she aggreed to have me ship it away for repair and if that fails my console will be replaced.
I am in australia too for anyone else from aus here with a similar issue.
so go straight to tech not to the live guys. hopefully i will get a fully working console back. but knowing M$ something else will go wrong. *knocks on wood*