iPhone disabled after receiving a call-worried if it is hacked
Recently I have received a call on my iPhone. While on conversation the phone vibrated 4 times with 10 seconds interval between each vibration as if I am receiving text messages. When the call ended shortly after, I looked at the home screen and a message "iPhone is disabled try again in 1 minute" displayed.
When I unlocked the screen after about a minute later there were no messages received and all of my apps have been re-arranged.
I am worried if anybody has attempted/hacked my iphone somehow. The apple id I use is an email where the email admins have notified me that in the past couple of weeks there has been multiple unauthorized attempts to get access to it.
Has anybody experienced this behavior?
iPhone 5s, iOS 8.0.2