How to resolve issues with parcels sent overseas from South Korea?

Hello, I am seeking help regarding an issue with a package my mother recently sent. Inside the package was TJ's bagel seasoning, which had previously passed without any problems, but this time it got flagged, and I received a message about it. They stated that the seasoning needs to be discarded and that I should add that item to a new invoice and send it again. I have already sent a new list based on someone else's advice, but they quickly replied that it needs to be sent through the post office. My mother tried, but since the package had already been sent, the post office said it couldn't be done. Has anyone experienced a similar issue? I would appreciate any advice on how to resolve this.