You can restore your purchases by following these steps:

1. Go to the Shop (tap on the top right corner SHOP button that shows the amount of Mana you currently have)

2. Tap on the "RESTORE PURCHASES" button

3. If requested, please enter your iTunes / Google Play credentials

4. Wait for the Verification process

5. Once verified, the game will confirm you the purchases have been restored to your account

Have fun playing, using your previous purchased contents!