A group of American influencers have received backlash online after they visited a fashion factory in China as part of a tour sponsored by online shopping giant Shein and posted rave reviews.

Shein is among several companies founded in China whose actions have raised questions over a range of issues, including how it is able to sell goods at such low prices, how transparent its dealings with the public are, and whether working conditions and its environmental footprint.

In mid-June, influencers traveled to the southern Chinese metropolis of Guangzhou to see the company’s “innovation center,” a bright and spacious facility with high-tech fabric cutters and material-carrying robots.

Images showed smiling workers making clothes as the group toured the factory, while some of the visitors took part in the production.

THE Kenya Freemana designer who has sold clothes on Shein, traveled to China and Singapore, where Shein is now based, as part of the team and shared videos on her Instagram account.

Backlash was immediate, with comments critical of the company, which was accused of supporting the company’s alleged human rights abuses and the environmental impact of fast fashion.

The amount of online hate was “unprecedented,” Shein’s collaborator Freeman told CNN, and it affected her mental health. “I couldn’t even get on Instagram yesterday,” the Atlanta-based designer said, adding that she wasn’t defending the company or taking responsibility for its actions.

Freeman, who first partnered with Shein in 2019, said the fast fashion giant has been a lifeline for small businesses, especially those with founders from marginalized communities.

In a statement, Shein said the social media videos posted by the influencers were authentic. “Shein is committed to transparency and this trip reflects one way we get information about our product, providing an opportunity to show a group of influencers how Shein works through visiting our innovation center and giving them the opportunity to share their own ideas with their followers,” he said.

Shein is especially popular with Gen Z because it advertises heavily on apps like TikTok, cultivates close relationships with influencers and keeps prices low in a time of high inflation.

But its massive rise has raised questions about its practices, especially as relations between the United States and China have soured.

In April, a US congressional committee said Shein, online superstore Temu and others in China were potentially linked to the use of forced labor, exploitation of trade loopholes, product safety risks or intellectual property theft.