Troy,
I’m sorry the display is giving you trouble.
I agree with you that it does seem like there is no issue with the display itself. My guess is that some pins are not making good contact with the header pins. I often have to bend the display leads pretty far to get them working properly. Are any segments working on all three digits, or are only pieces of 1 or 2 digits working? Also, are the same segments not working on each digit? If we know which segment or digit is not working then we can tell which pins are not making contact.
Let me know.
Good luck!
-Brach