"What kind of person fakes illnesses for attention. She has mental health issues and needs help. It scares me to think how many people have died following her natural therapy cancer treatment diet/lifestyle. Disgusting," another Facebook commenter said.
Many others called for the entrepreneur to face up to her lies and do the right thing. Questions have also been raised about her donations to charity.
Ms Gibson shot to stardom on social media and gave hope to cancer sufferers worldwide after she revealed that she had prolonged her life despite shunning conventional medical treatment and relying on her own 'whole life' concept.
She told her social media followers last year her brain cancer had spread to her blood, liver, spleen, uterus and that she did not expect to survive.
It has been reported that Ms Gibson has met with lawyers to fight the claims.
School friends of under-fire Whole Pantry founder Belle Gibson now query whether the health guru invented stories 'to get sympathy' and warned people against vaccination while she was in high school.
Ms Gibson attended Wynnum State High School in Brisbane and former classmates describe the health guru as a "drama queen" who constantly reinvented herself and backed medical cannabis.
Former school friend Chris Green said Ms Gibson was "a drama queen. There was always something going on with her."
"At one stage she was an emo, then a skater girl then she was a surfer chick; she was always something different,' Mr Green told The Courier Mail.
Mr Green also said that Ms Gibson never mentioned an autistic brother or a mother with multiple sclerosis, who she had previously claimed to be a carer for.
One anonymous school friend said that Ms Gibson would often post information advocating against vaccinations and pushed the viewpoint quite hard.
Former classmate Meg Weier said that Ms Gibson was quite strange.
Friends close to the mum-of-one have said that she may have gone overseas to avoid confronting claims that her remarkable cancer survival story is not all it seems.
Another former friend of Ms Gibson has called on her to "come clean" on her "misdiagnosis".
Mother-of-two Jayne Smith, 28, from Sydney, became a confidant of Ms Gibson's after they met on a parenting discussion page on Facebook around 2010.
They forged an online friendship and confided over their experiences with cancer - Ms Smith having lost her mother to lung cancer in 2003 and Ms Gibson saying she had brain cancer.
Ms Smith told Daily Mail Australia she was "baffled" when reports emerged this week where friends raised doubts about Ms Gibson's medical diagnoses and charity donations.
"I am just so shocked and I feel betrayed, that we all fell so hard for the illusion that she created," Ms Smith said.
"It has hit all of us, who I know, (who) also know Belle, like a tonne of bricks."
"We only knew her online, but we all believed to a point that she was a genuine pioneer, who was surviving aggressive cancer.
"Belle and I talked quite a bit about my feelings about (cancer), how she could empathise with me, the feelings I felt about my mother dying and how I'd wished I was more responsible when it happened, that I'd wished I had tried to explore more ideas, like Belle did."
Ms Smith said Ms Gibson "pushed" - and nearly convinced her - not to vaccinate her children, but that she did not blame her for nearly making that choice, which she "backed out of at the last minute".
"That was my own choice, based on information provided by Belle. I regret that choice (to nearly not vaccinate), but it was my own. I'm not here to place blame."
In November 2014, Ms Gibson told Sunday Style magazine she blamed the cervical cancer vaccine Gardasil for her cancer.
After friends and medical experts cast doubt on her medical claims in various media stories this week, Ms Gibson told The Australian she may have been "misdiagnosed".
"It's hard to admit that maybe you were wrong," she told the newspaper, adding that she was "confused, bordering on humiliated".
The company she founded, The Whole Pantry, said donations to charities that allegedly failed to arrive had been "accounted for and not processed" and that promised donations "would be honoured".
Me Smith said Ms Gibson had the "gift of the gab" and "needs to answer to these people (her followers), because they are good hearted people who deserve answers".
"I don't care about exposing Belle. I haven't spoken to her for months, years.
"I just want her to confirm or deny (her diagnoses) so people who put their faith in her, invested in her - they need to know.
"They need to know, if they've rejected conventional medicine on what she's saying.
"It's their lives, it's not a game."
After three years of sometimes personal exchanges online, Ms Gibson and Ms Smith stopped talking after the development of the Whole Pantry app.
"If I saw Belle now, I would just ask her to tell the truth. That's all I want.
"I don't want to see her beg people for mercy. I don't want her to beg for forgiveness - I just want the truth.
"Come clean, be transparent, let the world know where you're at. If you were misdiagnosed, own up to it.
"Belle DID create an exceptional application, that is loved by many, but I think she should sell it for what it is, complimentary medicines and a diet - not life saving treatment.
"All people want is the truth from her."
Close friends told Daily Mail Australia on Wednesday that Ms Gibson may have left for the United States. Police visited her home on Tuesday night to check on her welfare, but she was not there.
Multiple calls to Ms Gibson's mobile rang out.
- Daily Mail
