LCD backlight (lamp) not working

I get a dell inspiron 15 3542 about 5 months ago in Pakistan . unfortunately its LCD Baklight has stop working . LCD is working fine. Laptop is still in warranty . Can anyone help me to resolve this problem when dell support website is recognizing my service tag for Pakistan . I have the only option of live chat with agent . I am failed to get any contact number . But whenever I enter my service tag at the chat time  it do not recognize my service tag  as follow . I am sure that my service tag is registered for Pakistan .