Restore purchase from Google PlayTo purchase or restore purchase from Google Play, you may have to install the app using adb (or any terminal app).

use adb
adb install -i ‘com.android.vending’

use terminal app
su
pm install -i ‘com.android.vending’

This is because Google Play may refuse apps not installed from Google Play to initiate the purchase. The -i ‘com.android.vending’ in the command specifies the installer as Google Play.