Just for the record, I am seeing this message today as well. Even though the URL does redirect to: https://payments.amazon.com/withdrawsuccess, the transaction does not complete and my balance is unaffected. I contacted them here: https://payments.amazon.com/contactus though it would never hurt for other people to back me up with their own trouble reports.
Thanks for the updates guys. If you click on "View or Edit your payment information...." it routes you to the Amazon support site now. https://payments.amazon.com/help?