I used the sample AdMob app available here
to test the plugin and I can confirm that the plugin works as expected on our side. I tested on the following iOS devices:
- iPhone 5S running iOS 8.1
- iPhone 5C running iOS 7.1.2
- iPad running iOS 7.0.4
Can you please try the app on your side as well and let me know if it works as expected. Also, please make sure that the network settings on your phone do not deny the app receiving ads.