Quoted from CrazyLevi:Prospective buyers are under no obligation to respond after getting pictures. If you can't handle that, stop trying to sell pins.
You aren't mad that you aren't getting a "thank you." You are mad that the games aren't selling. If you really want to sell them, try lowering your prices.
I always respond to thank them for sending the photos and also to either indicate I'm interested or not interested after seeing them.