why is my ipod not starting even though im charging it? whats wrong?

My ipod is not working its just 1 month and a half. I was using it last few hours but it shuts down and charged it, i thought its just empty battery but its not charging!!!! tried to charge my ipad to check if my cable is defective but its working. I charged my ipod for 2 hours but its not starting (screen black) no lightning. HELP!!!!