How to organize customs clearance and customer service records when the reason for cross-border order returns is unclear

Two cross-border orders were returned to the warehouse this week, and the carrier's note only said 'customs issue'. Customer service didn't know how to explain it to the customers, and the warehouse didn't know if they could be resold. If the reason isn't clarified, the next batch of the same SKU will get stuck again. I started by checking the tracking events, commercial invoice, HS code…