Can't change default language in android developer console - Missing non-existent in-app product translations
I have an app with default language which is not English. I want it to be English. When I try to change the default language from Store listing > Manage translations > Set as default the following error appears
"Before you can change language to English (United States), you need to provide English (United States) translations for all your in-app products. Translations are currently missing for 9 products."
The thing is that we no longer have in-app products. As you can see from the image. 
The other problem is that Google support is helpless and despite the numerous emails and live chats they always need "more time" to investigate the issue.
The store in-app products visibility is connected to having a billing permission in the last APK. So I had to add another APK with BILLING permission and the in-app products became visible. Before that, I thought we don't have in-app products. I've added translations for them because active subscriptions can't be deleted. After adding translations for all products I managed to change the default language of the store listing.