During setup, RoboKiller asks you for your phone number. We do this for a couple of reasons:

1. To ensure that you have input the correct phone number and that you are registering your phone number and not someone else's (which we confirm with a verification code sent via SMS).
2. To configure RoboKiller to work properly with your mobile carrier.

We do not keep or sell your phone number, add you to spam lists, or any other types of services.