Why is this happening to me?

Psycho decided to start iming me tonight so I blocked him. He then got another sn and imed me and I in turn blocked him again. I was trying to send a friend a text and he called my phone and i accidentally answered it. I started yelling at him telling him I wanted nothing to do with him and he started telling me how mean I was and that he wasn't even treated this mean by his exwife. He tells me he bought me a bday gift that cost $150 and I say i will just mail it back to him. Finally I get so frustrated I hang up on him. He then proceeds to call again and I don't answer and he leaves a voicemail telling me how mature I am. I am literally shaking. My friend is coming over now because I am freaking out. I just want to be left alone. Can you block phone numbers from calling your cell phone? I think I am going to have a drink so I can stop shaking.