Over 500 attendees expected Disability Minister Bill Shorten would be making the keynote speech but organiser Devinder Singh told attendees this morning Mr Shorten wouldn't be speaking.
"I told the organisers a month ago I was unavailable," Shorten told 9News.
"And two weeks ago, we wrote to them and said please stop promoting my attendance".
The politician told organisers by email on March 7 to "update your marketing materials" to ensure "prospective attendees are accurately informed".
That didn't stop the organisers promoting the minister as the major attraction on tickets and online.
Marie Sabbagh from Assist Ability Australia, said the minister's appearance was why she'd bought the "very expensive tickets to this event".
"We weren't made aware until this morning that Bill Shorten wasn't going to be here," she told 9News.
Similarly, Peter Kartabani from Safe Place SA said he spent "thousands to be here because I was told Bill Shorten was going to be here".
Disability providers, participants and advocates had travelled from across the country attracted by the opportunity to hear from and speak to the minister.
Frances Kupke Smith, an NDIS participant, said she "wasted NDIS money" to not only attend the event but bring necessary "support to be with me".
9News attempted to speak to Singh did not answer our questions.
Bill Shorten told 9News he has "written to the ACCC today".
"I do not see the National Disability Insurance Scheme as a honeypot for anyone," Shorten said.
"Now maybe it's legal what this person's done, but I certainly don't think it's appropriate".
Bill Shorten has also asked the Speaker of the House to consider tightening guidelines for the commercial use of the Great Hall.
"I've been in the business for 28 years and I've never been to a conference that's been so badly run and it's got nothing to do with people that we are supporting," Carol Smail from ACL Disability Services told 9News.
