diemanstan

my ultimaker 2+ seems to have a problem the prints I am getting off it are ok size wise on the x and y axis but the z axis seems to print everything half size eg a cube 20 wide 20 deep and 20 tall will print 20 wide 20 deep but only 10 high any idea how I can cure this problem

upon building the printer several things trouble me the logo on the back of the bed is incomplete and reads ltimaker 2+ the hot end has no spring and looks unlike the manual downloaded from ultimaker and leaks filament the feeder is nothing like described in the manual and is made of metal not plastic and after a firmware update runs backwards