Airline passengers throughout the U.S. are increasingly taking to social media to air their frustration at not being able to get refunds for trips canceled amid the coronavirus pandemic. The U.S. Department of Transportation on Friday reminded carriers that they are required to reimburse fliers for fares and fees.

Hubs like Singapore, Abu Dhabi and Shanghai have halted most crew transfers, while global lockdowns have complicated travel from the Philippines, which supplies about a quarter of the world’s seafarers.

At risk is the flow of goods like food, medicine and energy via commercial shipping, which accounts for about 80% of global trade. While unseen by most consumers, restrictions on crews are among the unprecedented challenges wrought by the virus, which has ground major economies to a halt.

According to the complaint, Walmart did not follow guidelines issued by the Centers for Disease Control and Prevention and the U.S. Department of Labor for maintaining safe workplaces, such as implementing social distancing.

Walmart also hired new workers in an expedited process without properly screening them for symptoms of COVID-19, Evans’ estate says.

“The W.H.O. really blew it,” Trump said in a Twitter post. “For some reason, funded largely by the United States, yet very China centric. We will be giving that a good look. Fortunately I rejected their advice on keeping our borders open to China early on. Why did they give us such a faulty recommendation?”