Hp Laptop — no service by dealor

i have bought hp laptop some one and a half years ago from my college which had arranged from some dealor who came to our campus.they provided me 2 yr onsite warranty.nw my laptop charger is not working, i showed it to hp service center hp refused to replace it free of cost saying they give 1 yr warranty and its over but since i was given 2 yrs warranty by th dealor then he should do it for me but he has given me someone else number to talk. now i dont understand is it my duty to call so many people and talk about my problem, is it not the dealor's duty to solve the problem for me. iam annoyed very much and really harrased mentally. i want please someone help me out . iam without my charger since 2 months.