A blunder by lastminute.com saw a couple book a package to Kefalonia with a hotel 400 miles away.
The online travel agency advertised seven-night packages to the Greek island with a list of hotels to choose from, including the Skala Hotel.
Pauline Linger booked a £945 holiday, but when she received the Atol Certificate she noticed that the Skala Hotel was on the island of Patmos, near the Turkish coast and hundreds of miles from Kefalonia, in the west of Greece.
To travel between the two would take at least three days by ferry and car.
Gemma Antrobus, chairman of Aito Specialist Travel Agents, said consumers often do not recognise the value of agents until something goes wrong.
“I can guarantee you will never get the most value online; that will come from someone with contacts and experience,” she said.
Antrobus said that even if an error occurred, it would usually be flagged up prior to documents reaching the client.
Miles Morgan Travel owner Miles Morgan said one of the reasons agents are successful is their destination knowledge.
“If you look at my most successful staff, it’s down to knowledge, enthusiasm and smiles. They could beat a computer any day of the week,” he said.
“Agents make sure that you as an individual like the product we match you to. The likelihood of [a blunder like lastminute’s] happening in an agency is tiny.”
Lastminute.com blamed a technical error in the mapping of airports – there is a Skala in Patmos and in Kefalonia.
Linger was initially told that nothing could be done until 48 hours before departure, but lastminute.com has promised a full refund after it was contacted by The Independent, which reported the story.
In a statement it said: “The issue has now been fixed. Customers are at the heart of our business and their satisfaction is the number‑one priority for us.”