Samsung 5100 Battery Pack not working

[Android Central Question]

Hello,
I have a Samsung 5100 Fast Charge Battery Pack. But it wasn't working suddenly.
When the battery pack is connected to the electrical plug, the battery status will light up - showing full bar as I had charge it for quite some time.
However, once I unplug the battery pack from the electrical plug, the battery status will not light up no matter how I press the button. Similarly, I wasn't able to charge my phone with that.
Any idea how I can fix it?
Thank you in advanced!

 

[Rukbat]

The battery is probably shot, and it wouldn't pay to replace it. Samsung charges at least $60 for a battery replacement, and you can buy a new 5100 for $44 at CDW (or a larger fast-charge power pack for less at Amazon).