This is why I will not order from anyone who has anything less than a 100% resend policy. People with only a 50% resend policy obviously aren't very confident with their packing, and don't value customer satisfaction very much.
If someone sent me a pack which got received and refused to resend, I would demand my money back. Taking someone's money and not delivering the goods promised is scamming. Seizure or no seizure. It's not the buyer's fault it was seized, and he should not lose his cash.
The source has a responsibility to get that pack through customs, and when they fail, they should make up for it in either a resend or refund. Simple as that.
This is one more reason to get source checks because reputable sources do not pull this kind of shit.