If you purchased with iOS on Apple and would like to use your purchase on an Android device:
Create an account here on the website at picadomusic.com. On your iOS device in the app, click Settings-> Account at picadomusic.com and log in. Now switch to your Android device and log in there. Then your Apple purchases will be transferred to the Android device.
If you paid with Android and PayPal and want to use your purchase on an iOS device:
On the iOS device in the app, click Settings-> Account at picadomusic.com and log in. Your Apple purchases will then be transferred to the iOS device.