Boy trouble really scared i need help can anybody help me?

ok there's this guy and we've been lke best friends since i was 7 and a few months ago i started liking him but i knew he allready liked me and when ever i asked him if he did he would say no but then we were walking and he asked me to go out with him and i said yes but then he asked me when we were going to have and i just ignored him so i went home and the xt day i broke up with im and he keeps calling me ad i don't know what to do i never want to talk to him again i neve knew he was a ual harrer. and 'm young and i don't even want to have right now. how do i let this guy know i don't want to talk to him without hurting his feelings. i reall need help on this. i'm afraid if i talk to him he'll me or something. i'm scared HELP!