It was meant to be relaxing manicure and pedicure session.
But the Bahrain couple, here on holiday, were shocked after they were charged $1,259 for a one-off session lasting 11/2 hours.
It left Ms Michelle Ong, 36, and her husband, Mr Ali Hasan Aldhaen, 45, fuming.
"It wasn't anything special. Just a regular session. How could it have cost more than what five-star hotels charge?" said Ms Ong, who grew up in Malaysia.
The shop, Quiche Nail Spa at HarbourFront Centre, said the couple were told of the fees.
But the couple are disputing it.
"We were shopping at the mall and one of their staff members approached us as we passed their shop," recounted Ms Ong, referring to the incident on Nov 27.
"They offered us a $128 package each and we thought it would be nice to do our nails and relax," she said.
The couple entered the shop and started the session.
"During the session, the therapists asked me if I wanted lotion applied to my hands, if I wanted a mask or if I wanted nail extensions," she said.
Ms Ong claimed that the worker did not inform her that there would be additional charges. So she assumed it was part of the package.
She also pointed out that the brochure they were given seemed to indicate that services such as scrubs, putting on a clay mask and applying lotion were included in the $128 package.
"When I went to the cashier to make payment, I didn't realise how much the bill was at first because I was trying to convert the amount back to Bahraini dinar," she said.
It only dawned on her how expensive the session was after she had paid and left the shop.
"I turned to my husband and said it was too much. I was close to tears. I felt so cheated. We ran about the mall and to the information counter hoping to seek help," she said.
Said Mr Ali: "We checked that a manicure at our five-star hotel only costs $75. For $1,200, I would expect my nails to be gold-plated or something."
"We never expected something like this to happen in Singapore, much less a legitimate mall."
The couple, who were staying at W Singapore - Sentosa Cove hotel, returned to the shop the next day hoping for a refund.
This time, The New Paper, following a tip-off from a Singaporean who had heard about their case, accompanied them and observed what took place.
Ms Ong first confronted the staff member and demanded to know why she and her husband were charged so much.
Staff were overheard telling her that they had used different products that cost more.