Skip to content. Sign up Product. 2021. 10. 19. · Check your app data usage and see which app could be blamed for that. If there are anomalies, you can tell that your phone has been hacked. You may also notice that your phone bill has increased – yet you don’t remember making that many calls. It would be a sign to check your records for numbers that you didn’t call. To check if your iPhone is up-to-date, head to your device's settings, tap "General", and select "Software Update". While you're there, you can also set your iPhone to automatically install updates when they become available. 2. Change Your Passwords.