I noticed that the billing system came back up and the energy packages load once again. I decided to buy 7,500 energy for $20 through Steam. Upon purchasing the Steam wallet funds I hit purchase on SK and after a few seconds I'm given "An unexpected error occurred on the server" message with no CE obtained and a $20 USD pending charge on my credit card. Splendid...
Filing a support request in-game right now. Until then I advise anyone to hold off on tossing money at OOO in the meantime as billing is still clearly down but in a much more destructive way I guess.
I had the same problem with 750 energy right now -.-