LadyFenrirUnchained

I've never made a post here before other than the first one but I am finding myself in need of artists advice, as I am not sure on the precedent for the situation.

Long story short, I commissioned something from an artist. They made it, I was happy, I moved on.  I recently found the commission for sale else where and was shocked, assuming it had been stolen.  Only it was in fact, the artist I paid selling it.  Is this considered an approved thing to do?  I know they made it, it's their art, but it was a personal piece to me that I paid for.  Insult to injury, they are selling it to others for less than what I paid.

I am finding myself heartily upset but I am not sure if I am even allowed to be?

I am a crazy cat lady who loves Star Wars a bit too much.  I enjoy being creative but I'm only mildly successful in actually creating what is in my head. My art "skills" never went past fifth grade and my style is best described as unfinished cartoon.   I enjoy being outside(in the summer, I'm Canadian and it's bloody cold out there!) and I love to take pictures even though I don't own a camera.(Yes that's right, I am that obnoxious chick on the bike path taking pictures of flowers with her cell phone. ) I'm an avid(and very amature) thrift store cosplayer. I also do some writing, usually based on dreams so most are fanfiction from binge watching things.  www.fanfiction.net/~ladyfenrir…