I would mail to their customer service. They have a contact form on their site. It's reasonable to think that they can tell you what's the problem, and possibly refund your money if it's unsolvable.
There's no real reason to think it's scam, even if it's in Ukrain. Still, it would be interesting to read about your experiences with them.
Hi, i,ve been downloading mp3s from a site called mp3fiesta.com, all works well, they play fine on windows media player, but when i transfer them to my mp3 player Matsui 120mr no sound comes out, plus it sticks as if it crashes when it gets to the file, other people had same problem so my player is fine, something about these files.