Please note that ntl reserves the right to block incoming email from mail servers that have been blocklisted as a result of spamming or other abuse. ntl may also limit the number of email messages a user is able to send or receive in a given time period. This limit will only affect very heavy users, and is designed specifically to prevent the ntl network being used to distribute spam.
section 9 of this website
http://www.home.ntl.com/page/userpolicy&source=ntlworld