If you believe that someone is tracking you with your Android, do this
- Back up your favorite apps.
- Factory reset the phone.
- Encrypt your phone. (This way nobody else can access your phone)
- For extra protection, you may add a PIN so that you can lock down them from accessing your settings.
- If you are going a step further, you can lock down your phone in kiosk mode with the help of any custom launchers or anything like that.
