I dont no what 2 do!?

theres a boy in ma form at school hu seems to do all he can 2 annoy me. all he seems 2 do all day is flilk bits of chewed up pens and take ma books thn whn i try 2 get them bk im the one hu gets told off for it and whn ever i ask him wht have i dun 2 upset him he jst ignores me and whn i ave tried 2 tell a teacher they tell me 2 ignore him bt its so hard. i dont no wht 2 do HELLLP