A 16-year-old South Sudanese girl was sold off for marriage to the highest bidder on Facebook in November, raising concerns that the platform has become a “latter-day slave market.”

A businessman from South Sudan outbid four others — which included a senior Sudanese government official — after the girl’s family posted a message on Facebook in October, calling for suitors to bid for her hand in marriage.

The post, which has since been deleted by Facebook, was accompanied by a picture of a tall, expressionless girl standing alongside an unknown man. Facebook says it removed the post as soon as it became aware of it, but by then the girl had already been married off.

Child marriage is illegal in South Sudan, but the practice remains widespread with more than half of all girls married before they are 18, according to Girls Not Brides, a global partnership of civil society organizations. The owners of the now-deleted Facebook post seemed well aware of this reality, telling their prospective buyers: “Competition is perfectly allowed in Dinka/Jieng culture.”

A multimillionaire business tycoon from the country’s capital city of Juba named Kok Alat won the auction, after offering 530 cows, three Land Cruiser V8 cars and $10,000 in exchange for Nyalong Ngong Deng Jalang’s hand in marriage. The final bid prompted local media outlets to dub her the “most expensive bride in Africa.”