Ms Jill Foo was packed and ready to check in for her flight to Germany when she was told her $1,443 ticket had not been issued.
Stranded at Changi Airport, the 51-year-old called her travel agency Zuji repeatedly but there was no response.
"I asked the girl at the counter to check again and again. She couldn't find the booking," she said. "I was so shocked."
So as not to disrupt her travel plans, she paid an extra $2,527 for a replacement ticket, hoping to settle the matter on her return.
The sales executive has made a police report, sent Zuji numerous e-mails and taken the matter to the Small Claims Tribunals. She managed to wrangle a refund of $1,443, but nothing for the new ticket.
The Consumers Association of Singapore (Case) has received 48 complaints against Zuji since 2011 - 13 in the first half of this year. It is the only online travel agency to have received complaints.
Overall, complaints against travel agencies are rising. Case received 732 in the first half of the year, 1,436 last year, 1,396 in 2011 and 994 in 2010.
Gripes range from unsatisfactory service to the inability to obtain refunds.
Case cited a case in February of a group of eight who paid $1,320 for a two-day trip to Bintan. The package was to have come with free meals and massages, but when they got there, the group was asked to pay for them.
As Singapore's appetite for travel has grown, so has the number of new players on the market.
According to a 2012 Euromonitor International report, outbound tourism here is set to grow at a compounded rate of 2 per cent each year to reach 16 million trips by 2016.
This, said the National Association of Travel Agents Singapore, has led to new operators muscling in on the action. There are now 1,122 active travel agencies here, said its spokesman, up from 975 in 2010.
This cut-throat competition is one reason for the rising number of complaints, said Case executive director Seah Seng Choon.
"Some agencies cut corners to try to reduce costs, others oversell their packages to get customers to sign up," he said, pointing out that certain companies have cut costs by outsourcing bookings to offshore call centres.
Zuji's senior marketing manager Yvonne Du said that when the company first opened here in 2002, there were "no real competitors in the online space for travel".
"Now we have brick-and-mortar shops selling packages online, customers have more choices and they require us to go the extra mile," she said, adding that this can be difficult as Zuji has no physical sales counter here.
Instead, bookings made in English are routed to the firm's call centre in India, while those made in Mandarin are channelled to its other centre in Guangzhou.
Admitting that the agency has received complaints about the service of staff at the centres, she said that trainers are sent out to them once a month.
"The rationale to move our call centre out of Singapore in 2007 was a cost issue," she said, adding that it is difficult to monitor quality this way. "It's a challenge for us, but we're working on it."
As for Ms Foo's case, a mistake was made, said Ms Du. Staff at the call centre gave confirmation when the flight had not been booked. The agency is working to resolve the issue with Ms Foo.