"Do not resubmit" usually means it breaks multiple rules, its telling you not to submit it again, not that you have already submitted it. (there is actually a submitted multiple times option for declining/accepting customs.)

As for why it was actually rejected I'd say.

• Too Small
• Doll body (if what santa said was true)
• The second image looks like it may be a jpeg so, wrong file format
• Possibly transparency issues if you didn't check the transparency box.

So no, it isn't the staff team's fault. Its messed up in a ton of ways.