Ignore the reviews that say this app doesnt work. These people probably didnt take the time to read the instructions, which explains that you must FIRST enable your "Do Not Disturb" within iPhone settings, and change Allowed Calls to "Call Manager Group". Without changing these settings, the app does not have the permission needed to block calls. Having said that... the app worked for me, and I love the fact that it can block a call without even lighting up the screen or anything. It just shows in your missed calls next time you turn the phone on. HOWEVER.... one HUGE downfall is that ALL YOUR TEXT MESSAGES WILL BE SILENCED, EVEN FROM "ALLOWED CONTACTS." The iPhones Do Not Disturb mode silences all sounds except for alarms and CALLS from allowed contacts. The iPhones Do Not Disturb mode always silences all text messages, so even if you add the person to your allowed contacts, that only allows them to call you. The iPhone will still silence all SMS, iMessage, etc.