Naya Health, the maker of a $1,000 breast pump that was supposed to be "revolutionary," has shut its doors after the company was unable to find an investor or buyer.

The start-up emailed its users on Wednesday about the decision and took down its website. The email was forwarded to CNBC.

"We are sorry to have stayed silent for so long," wrote Janica and Jeff Alvarez, the company's founders, who are also married. "We have been working to find a way behind the scenes to either raise enough capital to face the increase in manufacturing costs or find the company a new home."

Women's health companies have struggled to raise funding of late and have also faced challenges with their supply chains. Naya had specific technical issues with its products, and users were disappointed with lackluster responses from customer service.

Several women previously told CNBC that their pumps arrived with missing parts, and others said their device stopped working after a few weeks. Many turned to online forums and social media to complain after they didn't hear back from the company.

Naya, which had raised about $5 million, was "unable to take it to the level we had aimed for, and our customer's deserved," the email said. The company apologized for its lack of responsiveness and said that users who have requested refunds but not received them should contact their bank or credit card provider.

Alvarez told CNBC in 2017 that she was living off minimum wage to get the company off the ground and had booked more than $1 million in sales. She described her mission as creating a more comfortable pump for women after breastfeeding her own children.

"I am still proud of what this company has achieved and the public conversation it has sparked about the need for companies to develop and improve upon the technology and tools available to help women live better and healthier lives,' the email said. "My hope is that others can build on this progress."

Here's the full email: