Cassandra Chiu, 35, has resigned from her part-time position as the Guide Dogs Association of the Blind's (GDAB) clients services manager.
She was meant to be an ambassador in that role.
Her resignation comes in the wake of a blow-up at fashion store Zara at Takashimaya Shopping Centre on April 10, when she and her guide dog Esme were allegedly turned away.
She turned to social media to tell her story.
She previously had similar issues with Forever 21, McDonald's and Haagen-Dazs - incidents which she also posted about.
In the aftermath of the Zara incident, the security guard - who is contracted through a security firm - was removed from his position at the store.
The Guide Dog Association also sent a letter to The Straits Times' Forum page, saying that it would also "be investigating the incident".
Within hours of the letter's publication on Thursday, Ms Chiu resigned from her position at the Association.
Ms Chiu also owns a business at Tanglin Shopping Centre where she practises counselling for young people.
This article was first published on April 17, 2015.
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