Jessica Lowrey, who had won two business class tickets that entitled her to fly on British Airways anywhere in the world, arrived at London Heathrow to find that the flight had been oversold and that she would be downgraded to premium economy.

The woman, who was traveling with her mother, had won a contest run by Flight Centre last year. When she got to the airport, she suspected something was amiss when they were incapable of checking in the an automated kiosk and had to stand in line to speak with an airline agent.

“This was when we started to worry,” said Lowrey, who was using the prize to fly with her mother to Bali, via Singapore, for a two-week vacation. She overheard a woman telling a family that British Airways had oversold their flight to Oslo. “We eventually got to the front and a woman scanned our coupons. She called someone and was silent for what felt like 15 minutes. We could tell bad news was coming.”

The British Airways representative informed the pair that the flight had been oversold and that there were no Club World seats left so they had been downgraded.

“I was just in disbelief,” said Lowrey. “Probably the one chance in our lives to fly in luxury and we weren’t able to because BA had oversold. We went from buzzing excitement to utter disappointment.”

Club World features seats that convert into flat beds as well as White Company linens, generous three-course meals and a selection of complimentary drinks. Premium economy - or World Traveller Plus – simply offers passengers wider seats and a bit more legroom.

Lowery was then informed at the gate by two BA employees that since they were “guests of BA” they were first in line to be bumped and were not entitled to compensation. Paying customers have the option of being reimbursed in cash or booking an alternative flight.

“We got on the plane and were sat directly behind Club World which was a bit of a kick in the teeth. Being able to see, almost touch, what we could have had,” said Lowrey.

British Airways, which provides flights to Flight Centre for competitions, said that the terms and conditions clearly state that promotional travel does not ensure a seat in the requested cabin. “With the flight being extremely busy we asked two customers to move to our World Traveller Plus cabin. We look forward to welcoming them back on board in Club World on their return,” a spokesperson for the airline added.

As for Flight Centre, they released a statement saying, “Flight Centre has been made aware of this issue and is looking into the matter as a priority. We are currently investigating the circumstances surrounding this event. Flight Centre takes customer satisfaction extremely seriously and once all necessary details have been confirmed we shall be in contact with the customer.”

RELATED: American Airlines To Contact Overbooked Passengers Ahead Of Departure Time

Since airlines generally expect a percentage of passengers not to show up for flights, they double book seats. They base their calculations on statistics, which are subject to misinterpretation. The practice is legal. In the US, the probability of a passenger being denied boarding due to overbooking is 1 in 1,000. Most passengers who get bumped willingly volunteer since they are usually offered another flight as compensation or an upgrade.

“Compensation varies from £250 to £600 depending on the length of the delay and the distance of the flight, although an airline is allowed to negotiate a lower rate with those who volunteer to be bumped,” said Nick Trend, Telegraph Travel’s consumer expert.