Who unfriended you - no ads for Android
Simply log in and press "refresh friends list". Wait for your friends list to be imported and you are all set up. Whenever you want to check if someone deleted you, open the app and hit the refresh button again. You will see how many friends you added or lost since last time you checked. Press the "all friends" button and see the list with your friends, or press the "history of changes" button and check the list of all the friends you added or lost since you installed the app.