The mother of a woman who told 1,048 Facebook friends that she had taken a fatal overdose has questioned why none of them sought help until it was too late.

Simone Back, 42, posted a message on the social networking site after 10pm on Christmas Day saying: "Took all my pills, be dead soon, bye bye everyone."

Instead of trying to save her or get help, some of her online contacts left messages taunting her and arguing among themselves. One called her a liar, another said she "does it all the time, takes all her pills", while another said it was "her choice".

Her mother, Jennifer Langridge, 60, who called police after receiving a text message about her daughter's online note, said: "Nobody told me anything about it until the following day when I was sent a text saying 'get help'."

The alarm was then raised with police, who rushed to Back's flat. They took her to the Royal Sussex county hospital, but she died at 5.05pm on Boxing Day.

Langridge, who also lives in Brighton, said: "I am disabled so can't get up the stairs to Simone's flat. I called the police straight away. It is upsetting to think nobody did anything for my daughter."

She posted a note on her daughter's page, saying: "My daughter Simone passed away today so please leave her alone now."

It is not yet known whether Back saw any of the 150 online responses. Some Facebook contacts begged for her address and phone number, but it appears no one who lived nearby contacted police or sought her out in time to save her.

Back's friend Samantha Pia Owen said: "Everyone just carried on arguing with each other on Facebook … Some of those people lived within walking distance of Simone. If one person just left their computer and went to her house, her life could have been saved. These so-called friends are a waste of air. If someone has got problems you don't go around adding to them, you don't start attacking people who are already vulnerable … Facebook should put up a flag or button so that a post can be flagged up as a suicide threat, and Facebook should be able to contact the police."

Graham Bell, from the Brighton and Hove Depression Alliance, said: "This is a very sad reflection on our community. People need to be friends in the real world as well as in the online world."

A spokeswoman from the charity Mind said: "Loved ones can find it very difficult to know how to support someone who is experiencing mental distress, whether this is being communicated face to face or online. It is a myth that people who talk about suicide don't go through with it."

Back, a charity shop worker who described herself as seeking friendship, had previously spoken to online friends about her thoughts of killing herself. But some of the messages on her site show she was not taken seriously and her cries for help were mocked:

Sussex police are not treating her death as suspicious. An inquest has been opened and adjourned.

A Facebook spokesman said users' safety was of "paramount importance". It added in a statement: "We have a close working relationship with the Samaritans and have a process in place whereby friends and family who are concerned about someone can report it to us through the help centre." "A team of trained professionals are then able to review the case and the Samaritans will make contact with the person at risk. The safety of people who use Facebook is of paramount importance to us and this system is just one of a number of tools we have in place to help them stay safe."