If I get a bad product, the first people I call are the company that made it! Give them an honest chance to make good on their product, since humans are humans and sometimes mistakes are made. If they don't make good, then don't buy their stuff again. Its that easy.
I've got a soma cog on my beater fixie (bought because it was cheap, of course), and the machining is good, and the threads were clean and smooth. I mean, its still a 'budget' cog, but it seems like a basic quality product. If it wasn't, I wouldn't just whine about it on the forum, I'd call 'em up.
I just wish Chris King made their King Kogs in a track cog... Those things are machined works of art.
peace,
sam