The Facebook group, which was called 'The Survivors of 118 118', included posts from members describing callers as "stupid" and "lazy bastards".
One group member wrote that they wished they could tell a customer to "Engage that pea-sized brain of yours and listen to what I'm saying to you", while another boasted of writing the mobile numbers of customers on pub walls and internet message boards.
The company launched an internal investigation in May to identify the users, vowing to dismiss any staff connected with the group, which gathered around 100 members.
The group's pages were taken down today following an appeal by 118 118 to Facebook, although it is not clear what exactly caused the action. 118 118 has claimed the pages were defamatory of its customers.
A spokesman for 118 said: "What we have ascertained is that nearly all the comments where we have been able to identify [the poster] have come from ex-employees. They absolutely do not represent the views and attitudes of the vast majority of our staff."
This is the latest in a series of high profile incidents involving Facebook recently. Last week, Vodafone and First Direct pulled ads from the social networking website after finding that they were appearing on the British National Party's Facebook page, with the COI following suit over the weekend.
Antony Mayfield, head of content and media at search engine marketing agency Spannerworks says the stunt will backfire dramatically, causing much more harm to the two people behind the group than to the 118 118 brand, as originally intended.
"The two founders of the 118118 survivors group could be the losers from this story in the long term. Both have a number of national stories that mention their Facebook group that could act as a deterrent to future employees. Even before this the two have a large 'web footprint' of photographs, blog posts and forum entries that could be damaging to their reputation.
"What might have been seen as pranks and high spirits in one’s teens and early twenties can become the reputation equivalent of a bad, very visible tattoo in later life. Many people don’t realise that what they do and say online can often become part of their 'permanent record' on Google."