Brand new ipod nano worked fine and charged for 2 weeks. Now it will not charge with the charger it came with in the box - get the message "this accessory is not supported"

I bought a brand new ipod nano just two weeks ago. It came with a charger in the pack - power point charger and USB.

I have registered the product through itunes. Used and charged it for the past two weeks - until yesterday. The battery was low so I plugged it into the wall to charge. All I got was a message on the screen saying "this accessory is not supported". I've tried resetting the options. Plugging it into my macbook via the usb cord - while my computer is connected to power, as well as without power. It wont register in itunes when I open up the program. It's driving me crazy. I work in a remote area and wont be able to go to an apple store or back to the shop I bought it from for another week. Can anyone help?