Probably the best thing to do, would be to leave it alone since revenge isn't all that fun, I suppose.  Some people might enjoy it, I don't really. 

BUT THEY REALLY HURT ME

I thought you had a boyfriend already, so what does it matter?

THE THING IS THAT THEY ARE TRYING TO GET MY BF TO CHEAT ON ME WITH HER SO THAT I WILL HAVE TO FALL BACK ON THEM

If you can't trust your boyfriend enough to not cheat on you, then the best thing to do would be to drop him right then and there and leave it alone.  Ditch your friends and give them the cold shoulder for being childish jerks and hang out with those that don't do something like this to you.  Getting them back is just proving you're as immature as your "friends"

BUT HE TELLS THEM TO FUCK OFF AND LEAVE HIM ALONE SO I CAN TRUST HIM BUT THEY DONT GIVE UP.

Then that's when you cut them off and leave them with the cold shoulder.  Just let your boyfriend know then that it would probably be better to never talk to them again since they're jerks.  I mean, you say that you're 18 yet it just sounds like freshman drama.  And with that, I'm just making an observation of the situation

ME AND HIM ARE MOVING IN TOGETHER AND IM GOING TO  NYU WITH HIM AND SO ARE THEY AND EVERY TIME WE SEE THEM WE AVOID THEM BUT THEY KEEP PUSHING IT AND WONT LEAVE ME ALONE SO I HAVE TO DO SOMETHING.

Well, like I said, the best thing to do is just to drop it and let matters be.  I wouldn't know anything about plotting revenge or doing something to get them to leave you alone besides asking them to.  I mean, if they're doing this to get you to fall back on them, tell them that you're never going to speak to them and cut off from being friends with them.

OK THAT IS RIGHT DROP IT CUT IT THANX

THE THING IS THAT THEY ARE TRYING TO GET MY BF TO CHEAT ON ME WITH HER SO THAT I WILL HAVE TO FALL BACK ON THEM