What should i do?!?!?

okayy so heres the problem. my boyfriend is the nicest guy i know. hes so sweet. but his brother and his brothers best friend are . they are so mean. they dont even know me and they always make rude comments like i'm ugly and i'm a skank and stuff like that. i'm not ugly and i dont wear inappropriote clothes or do bad things with boys so how am i a skank? but its really bothering me because when they see me they say it to me. not only when im alone but also when im WITH my boyfriend. they say stuff like omg you could do better then that thing. i NEVER go to my boyfriends house because of this. they make these comments and school and when i try to talk to my boyfriend on the phone or at school they always do stuff like take the phone from him and say mean stuff. or when i hang out with him they say stuff like ewww ur going to that ugly things house because i hear them when im on the phone. they also say stuff to my boyfriend behind my back. stuff like ur girlfriend is so ugly and other ****. the other say after school my boyfriend and i ran into his brothers best friend and he was like omg i thought u would actually have a hot girlfriend you could do better then that ugly thing. then what pissed me off the most was when he said me and derek (my boyfriend brother) should hook u up with these hot chicks we know. RIGHT IN FRONT OF ME! i almost cried and i didnt say anything back because i felt ashamed. they have no right to treat me like this because i never said a word to either of them. my boyfriend sticks up for me every time and they still wont stop. please help me im crying right now. thanks :)