understanding dependency relationship in UML component diagram

I'm struggling at understanding UML component diagram.

I've just been through the "assembly connectors" and here's what I (think I) understood:

• the circle represents an interface, which I understand as a set of functions that a component can offer to the others.
• the half-circle... well, don't know how to call it, but it says something like "there's some functions I need in order to operate correctly". In the image, I guess that an order must have access to functions that return details of the Customer (e.g: methods GetName(), GetAddress(), etc.), that's why it has the assembly connection with the Customer Details interface, provided by Customer.

My question is: why is there a dependency relationship arrow from the interface which Account provides (AccountDetails) and the interface which Order requires (Payment)?

The link of this image doesn't explain it.

The assembly connector (two shown on top) is a kind of provisional concept. You know that there should be an interface used instead, but have not yet made up the details. This is a connector which looks like socket/lollipop. But it's a connector.

The separate lollipop/socket are concrete interface uses. These are real elements. The interface itself is not actually shown (you will have a separate diagram showing the details). But to make clear that the depending interface is related to the providing one you draw a dependency.

Simply spoken, the above is something in the middle of a design phase. Finally all assemblies should be replaced by provided/required interfaces.