Need more details. What do you mean: "cant charge my phantom 3 battery"? That's a very broad statement. What happens when you plug the charger into the battery? Nothing? Doesn't light up? Lights up but won't charge? Details.
Can you try another battery to see if it's a charger problem or a battery problem? Do you have a voltmeter to check the output of the charger to see if it actually works? This is a dumb one so don't get offended, but are you sure the wall outlet you're using for the charger has power? Lots of simple things to check before giving up on the battery.