I have been searching but i haven't found any link for the datasheet of the coin acceptor. As i explained i tested using "CHANGE", "FALLING", "RISING", and "LOW" and described what output i got. I'm sure that i connected the correct line to digital pin 2 to read the pulse from the coin slot.
http://e-gizmo.com/wordpress/?p=895
i double checked the connections and i'm sure that the ground of the Arduino, Coin Slot, and LCD are all connected. I also checked the voltage supplies of the LCD and the Coin slot (5V and 12V respectively) and i'm sure its right.