It happened to me once with an article I posted on my website. Someone uploaded it to whatsapp and a writer published it as his own on his site with his name on it. He is supposed to be a doctor and a teacher, and he is very famous in Latin American networks. I never wanted to expose it. I ended up closing my page because I preferred to stop paying and use a platform like this, free. I write because anyway, even if it's not on Medium, plagiarism is the order of the day. A shame.