I agree with Chili, you can probably get an exchange either through your retailer or through Yamaha. Might be a pain to do it through the manufacturer, I've never tried that with Yamaha (never had to!). Or you can just take it for what it is, and love the guitar anyways.
I'm a big fan of Yamaha's entry-level and mid-level gear, I think that they're a great company that brings well-engineered and (usually) well-built stuff into the reach of us mere mortals. Sorry to hear that you had a defect on your guitar. I think that they make the best student and entry-level acoustics around.