"Trust, but verify" is a Russian proverb President Ronald Reagan often used when he discussed U.S. relations with the former Soviet Union.
Due diligence is to check facts. Not long time ago was it necessary to hire an investigator to do this. Thanks to internet is this process much easier, but it may still be hard to find the information you are looking for. Not all websites are in a language you can understand, and not all of the countries have their company registries available on internet.
If you want to buy electronic equipment, you have the choice to buy it from a shop or to order it online from e-commerce companies like Alibaba or Amazon. In most cases does this work well, and you will receive the product at your doorstep.
But if you want to find sellers of commodities or bank instruments on Alibaba or other sites, the story will be very different. Every "seller" of such products are false. Every one of them. Some of them may not even know that they are false sellers, because they believe that they represent a genuine seller. Such misled agents are called "Joker brokers".
And behind stands a group of scrupulous people who are using their persuading skills to grab your money, either you pay them a "fee" to become their mandate or you pay a "export license fee" to be allowed to buy the product.