Win8 upgrades failing - payment processor to blame?

I just went to upgrade to Windows 8 and was met with "initializing checkout failed".

http://gyazo.com/71da564b10515155cd2b1136d0ab6464

The thread above indicates that people can't call in either - MS and/or their payment processors seemed to be overwhelmed by volume. No doubt this may be spun as a "good thing", but 'selling out' would be a better headline than "no one could buy".

I'm flummoxed as to why one of the mega companies on the planet, with billions in revenue, and more than a year to prepare for a company-changing product rollout, can't accept payments for something on this scale.