The US has suspended visas for domestic workers of Malawian diplomats after an official failed to pay damages to a woman she had trafficked into the country.
In 2016, Fainess Lipenga was awarded $1.1m (£860,000) after a lawsuit against her employer at Malawi's Washington embassy, Jane Kambalame.
Ms Lipenga worked for less than 50 cents an hour and was mentally abused.
Kambalame has denied the allegations made against her.
A US State Department spokesperson told the BBC that the Department had informed US Congress on Wednesday about its decision to suspend Malawi's A-3 visa privileges, which allow foreign officials to bring domestic employees into the US.
"My life was miserable," Ms Lipenga told PRI news agency in 2017.
She began working as a maid for Kambalame whilst in Malawi, and went with her to the US after she was made a diplomat in 2004.
Despite having a cordial relationship before the move, Ms Lipenga said Kambalame took away her passport, locked her in the house, and listened in on her phone calls.
For three years, she was forced to work 16 hours a day, seven days a week.
"She told me: 'I'm a diplomat, you'll never get me in trouble'," Ms Lipenga told the Thomson Reuters Foundation.
No-one at Malawi's Washington embassy was immediately available for comment.
Kambalame - who did not take part in the lawsuit - was appointed Malawi's High Commissioner to Zimbabwe and Botswana in 2013, and has since left the US.
The BBC was unable to contact her to comment on the case.
According to the Maravi Post, a Malawian newspaper, she insists Ms Lipenga fabricated the story in order to remain permanently in the US.
In a statement published by the paper, Kambalame said Ms Lipenga had left the embassy without warning shortly after handing in her resignation. She added that they spoke several times afterwards, and that she visited Ms Lipenga in hospital where she was being treated for lupus.
"What sort of demon would have suddenly possessed me... that I would turn into a monster?" said Kambalame, according to the Maravi Post. "What would be gained from imprisoning her?"
Around 400,000 people are believed to be trapped in some form of slavery in the US, according to human rights group Walk Free Foundation.