Pantech Impact charging help?

I just got my brand new pantech impact today, like an hour ago. It had a low battery so I hooked it up to the charger and all I got was a message that said "check battery". So I turned my phone on and the battery icon just had an exclamation point in it. So I unpleges it and olives it back in and the check message thing came back on. I tried plugging a lamp into the same outlet and it worked so it's not that, but when I unplug my phone fromthe charger, it just dies. How do I get it to charge???