oh wow, that's a totally different issue than i had (mine came with a missing key bumper...key/aftertouch was functional but it wouldn't go down, pretty simple fix)
that's unacceptable man, return it ASAP. it's obviously been opened and messed with, and that's insane that it was old as brand new.
who knows what other trauma this unit has endured, and what potential problems will reveal themselves down the line...