every mobile phone has a unique serial number a.k.a IMEI, the number usually sticked on the battery tray and on the original box of the phone. If u got this number, u can ask the service provider (Qtel in this case) they can track whose sim card is using your phone & they can even block them. And of course the Qtel will ask from u first the police report bfore they can do you a favour... correct me if i'm wrong