J'ai acheté l'application via le Google Play Store, mais je n'ai pas reçu de clé d'activation pour la débloquer.

There is NO license key for purchases made on the Google Play Store.

The process is fully automatic with your Google account. You should see that the purchased version or feature is unlocked. Otherwise, please restart your device and check again.
If you have a MY.PROTECTSTAR user account, you will not see any license or edition listed for purchases made on the Play Store.

For more information, please visit: https://www.protectstar.com/en/faq/i-purchased-the-app-from-the-play-store-but-havent-received-an-activation-code