We try very hard to ensure that RoboKiller does not block wanted calls, but occasionally a wanted call can be blocked. But don't worry, there are things that you can do to improve the service not only for yourself, but also the entire RoboKiller community.
Open the RoboKiller app and look for the blocked caller entry in your Spam Box. Typically it will say "Blocked Call" or "Blocked & Recorded Call." Tap the "Allow" button for the entry and this will do things: first, it will add that caller to your personal "Allow" list so that they are not blocked in the future and second, it will let us know that we messed up and try to get it better the next time.
Also, you can proactively add your own numbers to the "Allow" list at any time, using the "Allow" tab and manually entering the number. Any number on the "Allow" list will never be blocked and will always ring through.