If you’re using an iOS device, please go to the Tandem app, tap on the ‘Pro’ tab, press 'See more', and scroll down to tap on “Restore Purchases.” This way the app checks if there is an active subscription on your iTunes account and if so, will restore your Tandem Pro features.
If you’re using an Android device, make sure you are logged into the Google Play Store account that you purchased Tandem Pro with. Then, tap Menu > Subscriptions > Tandem > Restore.
If you are still having issues please contact us with your Tandem ID and a copy of your purchase confirmation receipt from Apple or Google Play.