If you are unable to access your subscription on the device that you purchased, please tap on the "Restore" button in the app to unlock previous purchases again.
This will work if you are using the same account with which you made the purchase.
To share your subscription on another device, please follow these steps:
Open Kiddopia on the device that you used to purchase it.
Tap on the Settings icon.
Then, tap on Sign In and follow the instructions (The app will ask you to use your Email/Mobile).
Once you have signed in, please follow these steps on all the devices on which you wish to share the app, using the same account to sign in that you used above.