If you open the RoboKiller app and see an error message stating: "Whoops! Failed to get accounts phone number", this does not mean your phone is at fault. This is currently a widespread issue with an easy fix. To resolve this issue, please delete the RoboKiller app, restart your phone and reinstall the app. This should resolve the issue you are experiencing. Our next app update will fix this bug.
To uninstall an app on iPhone: https://support.apple.com/en-us/HT207618
To uninstall an app on Android: https://support.google.com/googleplay/answer/2521768?hl=en