I am really annoyed!! :( PLEASE HELP 10 points?

I feel so effin stupid!! well my brother's friend stares at me every time he sees me,all his friends nudge him and stuff.He added me on Facebook and I accepted him so he mailed me straight away asking for my BBpin I said I don't have it then he started chatting to me,so i went along with it..at that time,my brother was at his house..today my brother came to me and 'why did you accept my friend on Facebook and why the hell have you been mailing for,he said that you started mailing him and you were flirting' when this wasn't the case :/ I'm sure he has been going telling my brother's friends that I like him and I added/mailed him so he'll look cool..I seriously hate him.. I'm feeling disrespected! i also feel like an idiot for being nice to him..what do you think i should do? I don't wanna ever speak to him again or give him attention in my life!! if I unfriend he is gonna make more lies up!!