Exactly the same reason why I have never set up a DD. In the 4-5 years I've been with Telewest/Virgin, they have got maybe 1 or 2 bills right. I got bills for 2 phone lines and 2 BB packages for nearly 18 months. And when I upgraded to VIP my first months bill came to nearly £400.
It was actually only £93, so I can see how easy it was for them to make such a small mistake
