Sounds like that's in breach of your contract with them so judging by this. I'm not sure what technical aspects of the setup are affected by disconnecting the phone line though?
Yep, you're supposed to keep the phone line connected for a year.
And if you intend ordering box office movies etc on a regular basis - you should keep it connected & order via your remote. It's more expensive when you call them to order something, about €2 euro a pop more, I think.