THERE’S often a cost to doing things on the cheap. Just ask Chen Cheng, a local website editor who booked a flight from Beijing to Shanghai through an online ticketing agency at a price 10 percent below the fare quoted on the airline’s official website.

Chen found himself stranded at Beijing Capital International Airport for a whole day after his flight was unexpectedly cancelled. He was unable to transfer the ticket to another flight nor get a full refund on his ticket. In the end, the trip home cost him way more than the initial ticket savings.

When Chen posted details of his misfortune on his WeChat account, he received feedback from many other people claiming to have suffered from similar experiences.

“Why have online travel agencies become so unreliable?” he angrily asked in an interview with Shanghai Daily.

Good question.

The Shanghai Consumer Rights Protection Commission said it received 7,874 ticket-related complaints in 2015, a fivefold increase from two years earlier. It warned consumers that several online agencies, including China’s second-largest, Qunar Cayman Islands Ltd, were offering non-existent discounts, charging high service fees and refusing refunds on flight cancellations.

It’s all part of clever marketing, said Yan Yumin, a ticket agent at a small online agency mainly serving corporate travelers. In some cases, passengers simply don’t read the fine print detailing limitations on ticket transfers or refunds. In other cases, the tickets sold may have been purchased by agencies through backdoor channels and not from the airlines.

Public outcry about what many consumers feel is a scam has made some customers reluctant anymore to book tickets through online sites. What most travelers don’t realize is that the discount tickets they purchase may not have been intended for individual passengers, said Yan.

One trick used by agencies is to sell group tickets to individuals, since the carriers aren’t likely to know if the passengers onboard are part of one group or not. However, if an airline gets wise to the practice, the tickets sold could be invalidated.

“Passengers should always ask for the ticket number right after they book with the ticket agency,” Yan said. “For group tickets, the agencies receive ticket numbers from the airlines only about three days before takeoff.”

Another common trick used by online agencies is to sell individuals tickets that the airlines have issued on discount to associated companies, according to a public relations official at a major online travel agency, who asked that he be called only H for fear of job reprisals.

According to agreements that airlines strike with important clients or associated companies, the tickets give bona fide passengers up to 20 percent discounts. Agencies who get their hands on the tickets usually sell them for 10 percent off to make a profit, H said.

However, if an airline discovers that a passenger holds one of these misdirected tickets, boarding may be refused, he added.

“If cheap tickets on an agency website stipulate that ‘no full itinerary or ticket receipt is available,’ it’s time to get suspicious,” H said. The other trick exposed in a Ctrip.com scandal is exchanging airline mileages for tickets.

Most airlines operate “frequent flyer” programs, allowing accrued mileage points to be exchanged for gifts or flights. Almost all airlines prohibit trading in mileage points, but certain loopholes make the practice still possible.

H warned consumers that some online agencies that register frequent-flyer memberships when booking tickets might be stealing your mileage points on the sly.

The most common ruse used by ticketing agencies is to change refund and flight alteration policies on cheaper tickets.

Kevin Wang, a Shanghai white-collar worker, said he got caught having to forfeit up to half of a ticket price to get a refund from a popular online travel agency when his business itinerary required him to change flights.

“But when I checked with the airlines, they told me the ticket could be refunded or changed free of charge,” Wang said.

H said online travel agencies normally use the refund charges assessed on passengers like Wang to offset discounts to other passengers on the same flight.

“There is a probability that one passenger in 10 on a flight will have to change or cancel their ticket, so the refund subsidizes the other nine passengers and turns a bit of profit for the agency,” he added.

Ticket prices

Sometimes, ticket agencies will cancel tickets and buy new ones if airlines suddenly drop prices, but they don’t pass on any savings to consumers.

Consumers aren’t the only ones unhappy about the scandals. The China Air Transport Association said 90 percent of the complaints it receives are related to online tickets. When consumers are unhappy, it reflects badly on the whole industry, airline spokesmen said.

Air China, the nation’s flagship carrier, said in a statement that passengers have been complaining about online platforms arbitrarily raising tickets prices, altering the terms and conditions of ticket use, and charging fees for ticket changes and refunds.

Nine Chinese airlines, including Air China, China Eastern and China Southern, ended their partnership with Qunar last month because of complaints related to ticketing and refund issues.

Shanghai-based China Eastern additionally announced that it will pay the difference between prices charged by online ticketing agencies and those quoted on its own website. As an added sweetener, the carrier said it will also offer participating passengers 60 yuan in cash or 2,000 mileage points.

Budget carrier Spring Airlines sells more than 85 percent of its tickets directly to passengers, saving up to 75 percent on agency fees, according to airline spokesman Zhang Wuan.

Online ticket agencies are certainly aware of the public outcry.

“Ctrip.com has always warned its agencies to obey regulations and avoid cheating customers, but some of them use loopholes to evade supervision,” Xiong Xing, CEO for Ctrip’s flight ticketing business, said in a reply to recent scandals. He also admitted some agencies fabricate ticket numbers to avoid detection.

Xiong promised that the website will now do checks on every ticket issued through its platform.

“We will also offer triple compensation and full refunds to customers who are barred from boarding aircraft with tickets sold through Ctrip,” he said.

In a statement, Qunar said, “Qunar.com will cooperate with the China Air Transport Association to regulate ticket sales.”

So what’s the most reliable way to buy an airline ticket?

Booking directly through airlines is one obvious safeguard.

Yan said customers should also avoid buying online tickets sold at far below market prices. That’s usually a sign that something is amiss, he said.

“It is quite important for customers to ask for their ticket numbers and check them with the airlines immediately,” he added.