Take the battery out of the phantom.
Turn the battery on when it is outside of the phantom by pressing the button quickly then holding it.
it should stay on, if it turns off by its self then there is a problem with the battery.
B&H are great people and they should have no problem replacing the battery.
If the battery stays on then the problem may not be the battery just the firmware in the battery controller.
Check the little battery contacts under the main spades on the craft.
Make sure they can move freely. Use a qtip wight he cotton removed to carefully put the contacts in and let them sling back
they will travel only about 3mm or so.
make sure they move freely.
Download the assistant software from the DJI website for your OS.
Remove the props,
Trun on the transmitter first.
Make sure the main battery is fully charged.
Insert the batter into the craft.
Connect a USB cable from your computer to the phantom there is a soft white cover over the USB port on the opposite side of the craft where the battery is.
power up the phantom , do not start the motors.
Launch the DJI assistant software and do a full calibration first.
follow all instructions on the application.
After that turn off the power on the craft, then the transmitter.
let them stay off for 10 min or so.
Then power up the transmitter then the craft and start the software and do all the updates.
If that doesn't fix it then return it to B&H for a exchange.