The whatsit is not required to use the widgets. The widgets can perform functionally without the whatsit. The whatsit will allow you to do more things with your widgets, so you used them.
Does this mean you will get that free whatsit when you purchase more widgets? No, the manufacturer caught their mistake in packaging.
Do you have any rights to demand a free whatsit just because you got one once? No.
Assemblies built with AAX can be opened with Foundation, you have only lost the ability to create more AAX assemblies.
Ben H. Loosli