Is Warranty Valid on items purchased on eBay?

I recently purchased a pair of the Apple In Ear Headphones on eBay. They arrived in the retail packaging and seem to be 100% legit but have been having issues recently with popping sounds coming from the right ear. I called AppleCare and they didn't seem to know what the Apple In Ear Headphones even are and kept getting confused as to the EarPods that came with the device. Now my question is, can I exchange them for a new pair under warranty if they were purchased at eBay?

Steven