SDKBOX Inapp purchase , should i remove listener?

Hi there,
I have implemented SDKBOX in app purchases.
My question is if I set the listener to the plugin, when and how (code) should i remove the listener?
Can you attach some code of example?

The best place is the destructor of the scene?

If you have some kind of singleton with the listener then you don’t have to worry about destroying it.

Can you teach me how is the best mode to implement the listener as a singleton?
I have been using a listener on every scene I used it, but your way seems to be much better…
Many thanks sheriff