Call the police. Any caller that continously bothers another person is considered an act of harassment. In this case, I would call the police and report the number.
References :

There should be an option in your phone that allows you to block certain numbers. It’s like blocking spam e-mails, but for your phone. The way to do it depends on the phone though, it should probably be under settings or something.
References :

Put your number to the national do not call registry. I’ve been getting that a lot lately too, with the South Dakota Primary being today. I’ve been getting calls from Clinton and Obama. And I am on the national do not call registry, I don’t know if it applies to events like elections though. However, it should stop telemarketers from calling you.
References :

I rung the number for you and threatened to harm them if they continue hassling you. They promised they would stop. No thanks needed, i enjoyed the call.
References :

You need to answer the call, and do whatever they say to connect to an operator, then politely tell that person to remove your number, and that they are not to call you again. After you have done this, they are not allowed to call again. It is unwanted solicitation.
References :

thers a do not call registry for cell phones now put your number on that give like a week or two then if they call again get the buissness name and location and report that to the call registry and boom they get a hefty fine if not sued by the registry.
References :