Is there a wireless double-earred earpiece for iPhone?
Are you talking about a bluetooth headset? To my knowledge, they are predominantly single ear because they are meant to substitute putting a phone up to your ear.

However, there does exist bluetooth stereo headsets that can handle music and make calls using their built in microphone. They aren't nearly as compact however, and likely not as battery efficient.

Take a look at the Plantronics BackBeat 906 Stereo Bluetooth Headphones Set if that is what you are in the market for.

Do give the guys at the store a break when you return the product. You are a rarity to request a stereo headset as 99% sold in stores today are single ear piece units.