Our payment processor experienced a bug in July 2020 that caused a "pending" charge to appear on a customer's card, before the purchase was ever confirmed. To summarize: in anticipation of the customer completing a purchase, our checkout software would pre-authorize the card. This pre-authorization would trigger the "pending" status, and could take up to seven days to clear from a customer's account. This bug has since been fixed by our developers and should no longer occur during the checkout process.
You can be sure your order has processed through our system only when you receive an email confirmation from Bookshop with a purchase order number attached.