Scams are rife, particularly when some authors can rake in thousands each month – but high-profile victims of plagiarism warn ‘day of reckoning is coming’.
The Guardian has a fantastic summary of recent scams and all that plagiarism currently going on in the self-publishing world.
I would strongly recommend writers and readers alike give the article linked above a read.
And I would strongly recommend against using Amazon’s dodgy Kindle Unlimited/KDP Select reading/publishing platform (as opposed to Kindle Direct Publishing, which I have no issue with). As a writer, your work is being buried by scammers. As a reader, your money is going to those scammers, and you’re helping to harm genuine authors.