Check and make sure all three pitch servos are working, and check the servos connections. If all three servos work for fore-aft stick movement (on the right stick), and not left-right, then it's probably a problem with the TX, since the same three servos should move for left-right stick movement (I believe the Blade 400 is CCPM).

If that doesn't work out, then take it back to the LHS and have them make things right!