It’s easy to forget that even if a Kickstarter project meets its funding targets, the investment you made doesn’t guarantee a final product. That’s the situation faced by thousands of backers of the Ossic X headphones, who won’t be receiving their devices or refunds after the company announced it was shutting down due to lack of cash.

Audio startup Ossic set a $100,000 target on Kickstarter in 2016 for its head-tracking “3D sound” headphones, which are especially suited for use with virtual reality. The product obviously had its appeal: Ossic raised $2.7 million on Kickstarter and $3.2 million on Indiegogo, along with seed funding that almost matched what was raised by the 10,300 crowdfunding backers.

Despite raising so much cash, the company has now shut down due to lack of funds. Ossic says it would require “more than 2 million additional dollars” to ship its headphones to all backers. The company received more than 22,000 pre-orders for the devices, notes TechCrunch, and while 80 backers received the $999 developer tier headsphones in January, only 250 Ossic Xs were built and a few dozen shipped to Kickstarter backers.

Ossic has blamed virtual reality’s slow adoption rate and a number of high-profile hardware startup failures for its inability to attract extra investment. It added that issues caused by trying to meet the campaign’s stretch goals saw it burn through the money that was raised. Staff reportedly worked without pay and used their own savings in an attempt to keep the company up and running.

Those who handed over money for a pair of Ossic X headphones and received no items or refunds are understandably unhappy with the situation. Almost 1500 backers have joined a Facebook page threatening the company with a class-action lawsuit.