Have you established if your displays are common anode or common cathode?
Have you tested all the segments individually, by hand?
If not, use a low value series resistor, e.g. 220R or 330R. Connect it from one of the digit/common pins to ground. Then probe each of the segment pins with 5V. If any segments light, the display is common cathode. If none light, connect the resistor to 5V instead of ground and probe the segment pins with 0V. If they light, the display is common anode. Check each segment and then move the resistor to the other digit pin and repeat.