Paying for a failed order
(1) If you accidentally closed the worldpay window before completing your payment you can get to the worldpay window again with redoing your order by going to this link paymentadjustment.html.
(2) If you are suffering from error messages or blank pages then you may have a corrupt copy of the webpage in your internet cache. To clear your cache, go to tools/internet options in explorer and click on "delete files" in the temporary internet files section. You should now be able to use the site without errors.