Read the various posts.
Tiscalli are attrocious at billing and at providing any; cough; service.
They will even bill you when you have left.
What do you need the net for gaming or just general surfing?
Gaming wise freedom to surf is the best I've had for a while, although it is limited to 20hrs a week. But it does keep the heavy users off.
Plusnet offer a far superiour service than Tiscalli, if you just require general surfing go with them. And they respond to you're emails and any issues you have. Unlike this shower.
Hope this helps.