Apparently Marco Arment made an ad-blocking app for iOS called Peace, then after 2 days decided that he didn't want to be in the ad blocking business for ethical reasons and so pulled the app. He explains his reasoning here:

http://www.marco.org/2015/09/18/just-doesnt-feel-good

In this update, Apple has made the (apparently unprecedented) decision to proactively refund all purchases of the app, rather than requiring users to request refunds individually.