How do we monitor the stock level of the AliExpress seller. Imagine we start selling lots of items and suddenly we are told that the supplier has no stock?

How do we monitor the stock level of the AliExpress seller. Imagine we start selling lots of items and suddenly we are told that the supplier has no stock?

We use a Monitor which actively tracks stock. As well, we teach to find items with many suppliers in case one source becomes problematic. And in the rare case where we run into an issue, proper customer service can resolve this as well.  All of this is taught in the training :-)