Why sleep/wake button of iphone 5 unresponsive?

Bought my iphone 5 on dec 20,2012 from www.widgetcity.com.ph. Just this passed 2 weeks the sleep/wake button is unresponsive it's about 3 out of 5 chances. I noticed that the left most side works fine but the rest of the button is dead. I'm from albay, philippines and i don't have any access to near apple service provider. Any suggestions? Thanks!