If you can't restore your purchase even though you are a paid user of the old version of Flexcil and got a free upgrade, please see the guide below.
Check the purchase history from the App Store
To restore your purchase, you should sign in with the same account that you used for getting a free upgrade.
※ You may not be able to restore your purchase if the account you used to download the app and the account that you got a free upgrade is not the same. Please make sure to download the app with the account that you used for getting a free upgrade.
Please check your purchase records and see if you can see the purchase record as follows.
You can find the guide on how you can see your purchase records.
View your purchase history for the App Store, iTunes Store, and other Apple media services
If you can't see the purchase record from the account that you are currently signed in, please switch to another account and check the purchase history.
In case the problem not resolved, please contact our tech support.