Virgin Media said "no further emails are able to be sent in this manner" after some of its customers complained they were being spammed following a group email.
A Virgin Media spokesperson said:
A small proportion of our customers have received an email from one of our suppliers which, if they reply-all, it is sent to a wider group.
We’re investigating exactly what has happened ... We apologise for the inconvenience caused.
More top news
Because shooting is permitted all year round dependent pups are left to starve if their mothers are shot, says charity.
Businessman Shrien Dewani has accused authorities of a "witch hunt" against him, in his first public statement in years.
Professor Stephen Hawking has revealed the 'one mystery' he finds most intriguing in the world is women.