iOS/Mac
Your purchase is linked to the Apple ID that you originally used to make the purchase. This means that you must be logged into the App Store using that same Apple ID in order for the App Store to recognize that you have already purchased the app. Please check your emailed receipt and confirm you are logged into the App Store on your device using the correct Apple ID. Then it will show up under the Purchases tab and allow you to reinstall it from there. For more information, see here:
https://support.apple.com/en-us/HT201272#apps
In some cases we have seen apps accidentally get marked as Hidden in the App Store or Mac App Store, preventing them from showing up under the Purchases tab. If this has happened, please follow the steps here to unhide the app:
https://support.apple.com/en-au/HT201322
Android
Same as above, your purchase is linked to the Google Play Store account you originally used to make the purchase. You must be logged into the Play Store with that same account in order for it to recognize that you have already purchased the app.
Refunds
If you have ever requested and received a refund for the iPhone, iPad, or Mac version of Paprika, please bear in mind that Apple no longer permits refunded apps to be updated or reinstalled, and you will receive the following error message: This update is not available for this Apple ID either because it was bought by a different user or the item was refunded or cancelled.
For more information, see here: http://www.macrumors.com/2014/05/24/no-update-reinstall-refunded/
As far as we can tell, if an app has ever been refunded, Apple will not allow you to re-purchase the app using the same Apple ID that received the refund. Instead, you will have to create a new Apple ID and re-purchase the app under the new Apple ID.