how to locate my lost ipad air

Pls how can l locate or find my lost ipad? I lost my ipad cellular 16go in the month of july last year in france. I have try ro use FIND MY IPAD to locate it , immediately I sign in the person was online and have change my profile name .so i activate d sound and also activitive find my ipad with a message, my code postale, my phone number.uptill now the person didn't call me. Any time I sign on find my ipad is always offline. I didn't know if I can still find it.