Stalking

Stalking: Unwelcomed persistent phone calls, emails, visits, following...

Best way to handle this is; 

1) make sure that you have told the person to stop in clear language, 2) report it to the police and 3) ignore the person. 

When you ignore the person, you no longer are giving them control. And they will usually go away.

Image: http://annyjacoby.wordpress.com/2010/01/20/what-can-you-do-if-you-are-being-stalked/