You can cancel orders by posting here as you did, or by shooting an email to customer.service@paizo.com. So long as the order is tied to the account you posted with, your post above is probably enough.
No-one is at Paizo until Friday, maybe Monday, so you won't here back until then.
I've altered the front page message to display everywhere. As Dennis and Andrew have noted, Customer Service will be back in the office on Monday, November 26.