Selling something for a product they can't do!?

I bought a custom phone case from a seller. We talked about it, and it's here. I'll note that they had it in the drop-down menu, as well as me saying my phone model. As we talk, they sent me an example of where everything will go, and it's the wrong case..I tell them and send a pic of what the case should look like, and they tell me they can't do it. I did ask for a refund but it seems like its mostly up to them if they give me one or not.

Am I out of 30+ bucks or is there a way I can make sure I get a refund