I just had this issue :(
I was buying a Weekly Sale Bundle for my brother, and my purchase was cancelled for no reason... >_<
The last time I bought something from Humble Bundle was last Saturday (5 days ago).
UPDATE: Tried again later, and still I have this issue. I have just sent an "angry" e-mail to the Humble Support for this, asking for an explanation... >_<
UPDATE #2: With less than an hour for the sale to be over, and still no answer from Support (just an automated message)... So I tried again with no luck, until I had to change the payment method as last resort as I read somewhere else that that would fix the problem temporarily (it seems we are not the only ones and it is now a common issue), and that worked ^_^, but still, a really bad move from Humble Bundle. What a disappointment... :(
Post edited October 03, 2013 by Azrael360