Things work both ways. Sketch card artists are a small community and many of them are friends. You start calling people out and making claims - you may find it difficult to find artists willing to work with you.
I'm hesitant to call out a name until I'm certain I've been screwed. It may be a misunderstanding. I lost the artists contact information and have been trying to find it, but it isn't exactly my top priority. Once I get in touch with him, I'd be happy to call him out if he is in fact screwing me.