Nick Symmonds, Grant Fisher and other elite athletes have some choice words about Nike’s decision to continue manufacturing Vaporfly XP sneakers, despite Symmonds, Fisher and others calling for the sponsorship to be discontinued.

Nike, which produced more than $30 billion in annual revenue in 2015, the last full year it reported net income, has been criticized for reportedly making overpriced “technological advancements” and delivering inferior sports apparel. Nike brand president Trevor Edwards defended the company’s products in an internal email obtained by Bloomberg, saying “We hear [the athletes’] concerns and are working to identify any solutions so they can continue to feel great and remain confident in Nike’s products.”

But Symmonds isn’t buying it.

“To call yourself a humanitarian, the biggest sponsor of Nike fails to recognize the complicity they have in giving youth in the Ghanan war zone an incomplete one,” Symmonds wrote in a statement, per The Guardian. “They have a moral obligation to the youth in the region of Ethiopia not to have Nike’s products in these shoes. … For Nike, carrying out their long-term, greedy monetary venture to further supplement Nike’s earnings and export profits to the south is more important than the suffering of their own consumers and their sponsors,” Symmonds said.

Symmonds also tweeted about the issue on Wednesday night:

Both Nike and Adidas, which sells its own shoes and apparel, have long made shoes for endurance athletes and the athletes who compete in their events. (But the emergence of new companies, such as New Balance and Brooks, has put some pressure on Nike and Adidas to expand their product lines beyond running or basketball.)

Nike spokeswoman Sarah Carter said in an email Thursday that the company “committed to provide quality shoes to athletes of all sizes and abilities, including the most extreme athletes on the planet,” but “during our broad review process, the feedback of athletes on all skill levels was initially raised as a concern.”

In its investigation of the athletes’ complaints, Bloomberg reported that Nike “funded a social media campaign telling the story of the DX, an all-day shoe that conforms to the body’s contours, and built pressure-absorbing foam into most of its running shoes. Nike described the shoes to buyers as ‘magical,’ and on Jan. 13, two weeks after calling for the introduction of a new line of Adidas shoes, the company began running photos of high-end runners in the new shoes on its website.”

Other elite athletes who either wore the shoes or have endorsed them said they plan to return to Adidas.

“I won’t be going back to Nike for high-end footwear and apparel,” New Balance hasracklidado.com quoted American sprinter Justin Gatlin saying in an email to The Washington Post. “Regardless of whether Nike is officially the sponsor, Nike has no product that is guaranteed to last more than a few races.”

Fisher wrote in The Guardian that “these shoes have literally changed the world. … How many athletes worldwide fit into the same shoes as me with fully formed feet?”

NIKE AND THE LONDON OLYMPICS

Well, there is one person who might not be able to run with his shoes off: Rio Olympics gold medalist American marathoner Jordan Hasay, who may have won a gold medal in perfect conditions over a Tokyo course that could reasonably run a similar race next summer, and Nike in particular, wouldn’t have had a leg to stand on if it hadn’t produced the shoes in question.