When I signed up and put in my credit card details, they immediately cancelled my order and completely deleted my account. I had to resort to moaning at them on twitter to get them to unblock me, which they did. Bit of a rubbish start to the journey though.
Very strange, I've heard of multiple people having these sorts of issues with them, but it just worked when I signed up. Maybe they have some overzealous fraud detection going on?