Hi, Had the same problem but it was because the callback wasn't working. In my case I forgot to add s to http on the callback address in wporlpay when I changed to secure. Seems if the callback doesn't work Zen doesn't complete the order but it does set up a customer account and Worldpay does take the payment. We ended up looking stupid and phoning a couple of customers to say thanks for your money and your name and adress, what can we send you? Hope it helps. Cliff