Kara and Joe Youssef sold their two apartments, withdrew their life savings, gave up most of their belongings and, in late October, set out for Istanbul for the trip of a lifetime: a three-year cruise around the world, scheduled to depart Nov. 1.

But in late November, after months of behind-the-scenes chaos, the Youssefs were stuck in Istanbul, with the cruise company canceling the trip. It did not have a ship that could handle the journey.The Turkish company, Miray Cruises, had announced the cruise, called Life at Sea, in March. It claimed it would be the longest cruise ever — 382 port calls over 1,095 days — and a community at sea, with opportunities to explore the globe. Starlink internet and a business center would allow passengers to work remotely.

The cruise seemed ideal for a post-pandemic era, targeting people longing for an escape. With fares starting at $90,000 for an inside cabin and going up to $975,000 for a suite, the trip even seemed like a bargain to some prospective passengers, cheaper than living three years in many cities.

Within the first month of sales, more than half of the ship’s 400 cabins had been reserved. But putting together a cruise of this magnitude is a monumental task, requiring a ship large enough to carry hundreds of people, docking rights around the world and secure funding.

Like a high-seas version of the Fyre Festival, which promised a luxury music concert in the Bahamas and delivered cold sandwiches and makeshift tents, the cruise imploded. It has left people, like the Youssefs, frustrated and confused. Despite promised refunds, only a small portion of the money has been returned so far.

In an interview in December, Vedat Ugurlu, the owner of Miray, blamed a lack of financing and interest for the cruise’s cancellation.

“We tried everything to find a solution, but at the end of the day we couldn’t get the investors and we couldn’t sell enough cabins,” he said.

That has left Ms. Youssef, 36, a former humanitarian worker from Ohio, and her husband sitting in Istanbul with three suitcases and a carry-on, waiting for a refund of $80,000.

“They kept leading us on, making us hold out hope until the very last minute, just days before we were supposed to depart,” she said. “We sold everything we have to make this dream happen. We feel completely defeated.”