Poshmark has sellers download apps on mobile devices to sell their goods. I did this and Poshmark published my Apple ID password as my user ID on the site.
There was no way to remove the listing nor change my user name. I am not happy at all about having to scrap a password I have used for years. Poshmark knows their app does this but blames the user. If you need to reach Poshmark the only way seems to be on Facebook.
They will then remove your negative complaint and block you from commenting. Poshmark has has millions invested in it and they can't build a site or app that is safe for it's users. Nor can they afford customer support or tech support apparently. Be vary wary of Poshmark.
I created a Facebook page called Poshmark No if anyone else needs to complain.