What happens if someone trys to call me on my iphone when i have them blocked?

Mine is the iphone 5S. I blocked someone on my iphone cos they kept calling me and would not stop. What will happen if they tried calling me?

Added (1). I went to the missed call and clicked the "i" with the circle around it and clicked block user or whatever.

Nothing that doesn't work.

YES IT DOES. Once you've blocked them, they will not be able to call you. They will dial your number, but it will play a busy signal on there end and you won't even know that they called.