We sent an email to our SPS customers (most of whom have already contacted us) letting them know of the situation, assuring them Sage is working diligently on it, yada, yada, yada and advising them not to post any invoices with credit card payment info until further notice.
If this does not get resolved soon, the only solution I see is to keep track of those invoices to be paid by credit card, update them with no payment info, then wait and process them through a cc cash receipts entry if/when the system is back up. Of course, the same is true for pre-auth SO's.
@MyronStevenson what workarounds did you suggest?