There are multiple instances of this on FB in many different types of groups I have seen it in the Weight Watchers Groups as well as knitting groups.
I am so sorry that you have become victim of these attention seeking liars. I now only post my quilts and items I do to my personal page. And ... when I find one of these liars ... I automatically block them (even if it is not my work that they stole). There is one exception to this rule for me, I belong to Kathleen Tracy's Quilt group and will post in that group when I do a challenge.