why can't he just leave me alone?

This guy that i just became friends with no more then three weeks ago will not just leave me alone. First we were talking as friends and then we started talking to get to know each other and then possibly go on a date or something. I know him through someone else and didn't really know him so i wasn't really confident about going out with him.

I finally told him I just want to be friends and he gets mad and saying stuff about how he has no luck with women. Of course i'm not just going to give in and go out with him.

I just can't go out with him because he just seems like he'd be one of those possessive guys. He texts me non-stop. and if I don't text him within three minutes he sends me two more texts.

There was one time i didn't text him for four days because he was getting on my nerves and he literally sent me over 200 text. I just don't understand this kind of behavior. He even sent me a relationship request on facebook two different times. He wrote on my wall a lot and I just deleted the posts.

And when I say something like "i'm annoyed" he thinks i'm talking about him and just starts cussing me out.

I finally told I just don't want to talk to him and this just isn't going to work out. It's been 5 days and he just wont let up. He's been texting me non stop.

it's always Hey, what's up at least 20 times. Then it's just what's up. Then he puts question marks. Then he just tells me random stuff that he's doing through out the day, and non he wont stop messaging me on facebook.

Please help, because it's getting annoying.