HELP! Xbox Repair issue

Ok so in November of 2006 is when my xbox 360 first failed so I had it sent in for repair they sent me back a new 360 then in about mid 2007 this 360 failed, so I sent it to be repaired they did and sent me back the 360. Now this was before the new website repairing setup they got going, back then I did it over the phone and the service person said they would be registering my new console for me and renewing the warranty under all my personal information i gave them. But never In the over the phone talk did they ever ask for my windows live ID to link my serial number to it or my gamertag, but this new website repair service does ask for it. It makes you log into your windows live ID first and then register a console if you dont already have it registered with its serial number. I still try to but once i enter it it saysserial number already registered and just leaves me hanging! So what do I do to getthe repair order in if it says my console is already registered? I have only had 2 gamertags and I have tried logging into my live IDs its not listed under either.

I would imagine that the only way to fix this would be to ring up Microsoft