My mum and dad took away and hid left for dead 2!!?

They have seen the trailer with gore and bought it for me for christmas (on my list), but now they hid it and wont tell me were it is and i said ill do anything but nothing will change their mind plz tell me how to get it back.(they let me play modern warfare 2, gears of war 2 and asains creed 2) no answers like ur too young and its too gory e.t.c.