It seems I have this problem
The app is passed review and is currently in App Store. But employer is not satisfied with it and asks to provide any facts to prove my theory.
So is it possible to debug the production in-apps to show that I try to purchase an in-app with correct identifier? Currently I can debug only sandbox purchases but they work normally.
Like others have mentioned, it takes an indeterminate amount of time for everything to propagate across the App Store, including in-app-purchases. It's very common that they don't work in production immediately. After your app is indexed on App Store in-app purchases usually start to work also.