Xamarin.InAppBilling not firing OnProductPurchaseCompleted

Hello,

We implemented the Xamarin.InAppBilling component and we are in the final stage of testing it (static responses are OK).

When we do a test purchase, everything is fine except that OnProductPurchaseCompleted is not triggered (all other events work fine).

BillingHandler.HandleActivityResult() is successfully called upon ActivityResult, but nothing happens next (no error, no event, nothing).

The purchase is successfully processed (GetPurchases works fine).

All we can say is that ActivityResult always returns a 1001 requestCode and a "canceled" Result.

The problem is that since OnProductPurchaseCompleted is not called, the app can not respond instantly and need to manually check for purchase.

Has it something to do with the RESULT_CANCELED result of the attached activity? Is it related to test purchase? (should they return RESULT_OK upon fake purchase?)

Any insight welcomed!