Sydney woman calls out hairdresser who she says shamed and detained her for being $15 short.

A woman has publicly slammed a Sydney hairdressing salon online, claiming she was detained and left in tears by staff when she couldn’t pay the full $30 bill.

In a seething viral Facebook post over the weekend, Kerrie Davies wrote that she accidentally left her wallet at home when she went to the Western Sydney salon for a blowdry, and was only able to pay with the cash she had in her pocket.

“Mortified, I explain the situation,” wrote Davies. “Hairdresser tells me I have to get someone to bring the $15 [balance] and I’m not to leave the store.”

Davies claims the staff refused her offer to leave her phone and handbag behind as security, so she could return home and collect the money. They also reportedly denied her offer to electronically transfer the funds using her mobile phone.

Instead, she claims, they said: “We gave you a service and you are not to leave here until we are paid in full.”

Davies says she was in tears and expecting the worst by the time a security guard arrived, but he turned out to be somewhat of a hero.

"He looks at the Manager as if she has three heads, reaches into his wallet and pulls out $15, gives it to her and says to me, 'Just drop it in to concierge when you can. Sorry, I can see how embarrassed you are'."

Davies did exactly that - along with a $10 scratchie as a token of her appreciation. "Hope he wins a fortune!" she wrote. "Thank you security guard 'Drew' for being such a nice guy."

"And thank you with a big middle finger up," she wrote to the salon, "for being absolute arsewipes and going out of your way to make an unfortunate mistake as embarrassing as all hell."

Davies' post has attracted more than 42,000 reactions, 18,000 shares and over 11,000 comments in just two days, with several people offering to boycott the business.

Others have flooded the salon's Facebook page with negative comments and one-star reviews - at the time of writing there were more than 500.

According to a more recent post on Davies' page, the salon owner has since been in touch with her to apologise for the way she was treated and to notify her that all staff will undergo customer service training.

"Sad that it had to come to that," Davies wrote. "I am pleased, though, that Drew the security guard has been recognised and thanked by so many. Champion bloke!"