In order to solicit submissions for an anthology, you need to develop a clear brief outlining what you're looking for. So that anyone thinking about submitting a piece has guidelines that specify what style of writing, how many words, what topics and themes etc. It's no use just asking Twitter and then complaining that the responses aren't good enough.
Especially on a subject like poverty where you're asking people who are most likely not professional writers to detail their personal experiences.
If I were going to write about my personal experiences of poverty, it would be difficult and traumatic to bring it all up and try to shape it into some sort of coherent narrative. To then be told it wasn't up to scratch would likely compound that trauma.
So, I do think Unbound needs to take responsibility for not putting a proper editorial framework in place at the very beginning of this project, especially because they were asking for contributions from people already potentially vulnerable in all sorts of ways. And they should have checked out whether Louisa had any experience of working on such a publication and put in place proper editorial support at their end.
Louisa is a nasty piece of work. Hopefully, she'll retreat into ignominy and nobody will ever hear from her again.
Unbound should put their hands up and admit they handled this project badly from the start. And anyone who did submit an essay should be compensated for the full amount, whether or not it is published. That would amount to a "kill fee" that editors regularly pay and would mitigate some of the reputational damage this sorry saga has caused them.