Presto...going to your call log and at least on an Android this is true, pressing your finger onto the number will bring up a screen that let's you add it to the "Add to reject list". Does the same thing as that nifty app.
Yes, it's the RNC - call the number back and press "1" when the recording comes up to have your number removed from their call list. It's all automated so you don't have to talk to anyone.