The standard Ego batteries are not repairable.
When you say it doesn't take a charge, do you mean that nothing happens when you put it on the charger/usb port? There are a few versions of the passthrough batteries: The newest versions of the non-VV ones (ego-C upgrade, non-vv) do a light-show when connected by usb to a working usb port. The Ego C is also compatible with the standard Ego chargers.
It is rare for a battery to be sent out from the factory with a *full* charge (they SHOULD always have a partial charge, though). It should trip the charger when you place it on one, or when you connect the USB. However, these batteries are revised often, and I am unsure about previous versions of them.
Also, the battery may or may not have 5-click protection (5 quick taps within two seconds to turn it on).
If the battery is indeed brand new- as in, you just received it and it neither fires, nor does the light on the battery flash when you put it on the charger or usb, then it is most likely defective, or the center-post on the battery is an incorrect depth, i.e. it's *too deep* to connect with the charge leads or the atomizers you're using. If possible, try and contact the supplier- as Xaiver says, the worst they can do is say "no", right? But in all honesty, if this is a *brand new* battery and arrived in this condition, it would be classified as DOA (dead-on-arrival), and they should work with you with the issue.
Best of luck, happy vaping!