When I got my first 8830, it would go into a reboot mode as soon as the device was fully charged. I'm not sure how you can tell what it's doing, if it's in it's holster. I can only see my LED if it's in the holster.
I called Sprint and they had me Wipe the device, load the latest version of the device software, take the battery out (about a million times), and then finally sent me a replacement.
Call your provider back and force the issue... hopefully it has been less than 30 days since you got it... that makes it really easier to get a replacement.
My replacement has been perfect. Could be a bad batch... who knows... oops.. now I've started a rumor...