Free app doesn't up to pro version

I downloaded the free app and later i bought the pro version, but the app didn’t update to the pro version. If I try to download the pro version I have to pay again. How do I get the pro version without paying again?

There are 2 separate applications:

Google Play Help mentions:

“You can use apps you bought on Google Play on any Android device without paying again.
However, each device must have the same Google Account on it.”

Google is responsible for its store and the app purchases.
You can check Google Play Help to find previously purchased apps or contact Google Support.

I know but if i want download the pro app I have to pay again.

Verwendest Du den selben Google-Account?

Do you use the same Google Account?

I only have just 1 Google account. But in the free app you don’t need to login with a Google account.

Du bist im nicht mit Deinem Account angemeldet? Ich muss mich zum Download anmelden.

You are not logged in to with your account? I have to register for the download.

In the Google play store I am connected with my Google account, but in the free app there are no account details. And no possibility to update to the pro app. I think because it’s not linked to my Google account. But i cannot download the pro app without paying again. Normally if you buy in the free app an upgrade it automatically change to the payed version.
The payment is already shown in my bank account.

Das ist Tricky, da kann nur Google weiterhelfen. Bei mir funktioniert die Nutzung auf mehreren Geräten Problemlos. Immer vorausgesetzt ich nutze den selben Google-Account.

That’s Tricky. Only Google can help. With me the use on several devices works problem-free. Always provided I use the same Google account.

Like explained above, Free app is not updated to the Pro app, as they are 2 separate applications.

Pro app is a separate app which need to purchase + install it separately,
using same Google account for purchase + installation.

Google is responsible for its Store.
For Google Play problems everyone needs to contact Google Support.

I know there are 2 seperat apps. In the Free app it is possible to buy the pro app but that gave me no link or something else to download the pro app. So now I have payed for the pro app but have no possibility to download the pro app. I only have 1 Google account, so it’s not possible to buy it in another account.
The fault is in the free app…

In your 1-star review you mention that your purchase is not visible in your Google account?

Free app has only a link for Pro’s Google Play page where anyone can purchase + install it.
Everything is handled entirely via Google Play, Free app is not allowed and does not have any connection with anything.

Google is responsible for its Store and the Google Play purchases, not the applications!
So if something is wrong in your Google Play purchases, please contact Google Support.