Those are both roosters. Maybe something like a welsummer, hard to tell from the pic. If you bought them as hens a month ago, most reasonably knowledgable folks would have known they were roosters by the color. So, that seller was less than honest with you, or they made an honest mistake. I'd contact the seller and see what they can do for you.
those are 3000% roosters and they are not black sex links and could be several from partridge rocks to welsummers.