A foreign trade enterprise of China orders a batch of primary products from a new foreign customer and enters into a transaction at a port of CFR China. The contract stipulates that the Seller shall deliver the goods by way of voyage charter. Chinese issuing bank has also paid against documents submitted by foreign negotiating banks in accordance with the L / C. However, the shipping vessel has not arrived at the destination port after a long time. After multiple inquiries, it is found that the carrier was originally a small company, and it has been declared closed down shortly after the departure of the vessel. The shipping vessel is an old one, and both the vessel and the cargo are missing. It can be concluded that the seller and the carrier colluded with each other to defraud, leading to heavy losses for Chinese buyer. What lessons should we learn from the case