XBox Series X - unable to process a warranty claim, how do I get this moving?

So I have been 'lucky' enough to suffer a power failure of my new Xbox Series X machine and find myself frustrated at the complete inability of the Microsoft Support website to process my warranty claim.

Issue is as follows:

Console will not boot up. Power present at device - Xbox button illuminates and the power-on beep occurs. If the console splash screen appears there is no audio at all. After a short pause the console then switches off, not having got any further than the
splash screen.

Have tried a few hard resets and removal of power for an hour (twice), but nothing beyond silent splash screen followed by automatic switch-off.

I have tried:

1. Online Device Service & Repair webpage - returns a 'come back later' message at the 'shipping' part of the process. I have tried multiple times over the past 24 hours to get past this but to no avail. (see image below)
2. Online chat & telecon is 'not available' for this issue

I am getting increasingly annoyed at what appears to be a conscious decision on the part of Microsoft to stonewall me (and I suspect others). The clock is ticking and I am not able to use a device and service that I have paid good money for - it even offers
me the opportunity to pay an additional cost for expedited support. Given the money I have spent on this device and the fact it is under warranty I find this absolutely disgraceful!

I have never had a problem before with Microsoft or their services, but the complete lack of any tangible progress in getting this issue sorted is rapidly altering my opinion of this organisation and the way it handles issues and complaints. Any advice on
getting this unjammed is appreciated.

:)