Why are in-app purchases not working?

Question

Android

Unable to test in-app purchases in the Android app. I am writing in C#, but at the moment I believe that the error is not in the component from Xamarin. Calling the BillingHandler.QueryInventoryAsync() method, which should return a list of possible purchases, returns an empty list.
What I did:
1) Added a public key to the code.
2) In the developer's account, added the e-mail of the test account.
3) Created in-game purchases and activated them.
4) Collected in Release, published and uploaded to alpha version.
5) Installed the same version on the phone.
That is, it seems like I do everything according to the instructions, but nevertheless the shopping list remains empty. Maybe I missed something? Or is the problem still with Xamarin?

Answer 1

2) In the developer's account, added the e-mail of the test account.
this does not affect your case, it's just so that the money is not debited during the test
3) Created in-game purchases and activated them.
check that they are exactly in the active state
4) Collected in Release, published and uploaded to alpha version.
also check that the application is published and not a draft
5) Installed the same version on the phone.
versionCode must match what is currently in the market (versionName does not seem to be important)
Wait 2-3 hours for Google to update the cache
If this does not help, you can still make yourself a tester: on the avfa channel tab, click on the link to manage testers, in the window that opens there will be a link belowhttps://play.google.com/apps/testing/ <your package> open it and become a "tester" and you can try to install a test version directly from the market.
In general, I did billing a month ago (on a native application), these steps are more than enough to test payments.

Answer 2

Because in-app purchases are EVIL :)