NEED A BLACLIST NUMBER

They stole my daughters Blackberry and the insurance needs a Blacklist number. I have given the call centre agent my names and Id number but then she asked I should give the 3 last numbers that was dialed from that cell phone. I could only give her two so she said she could not assist me. REALLY, what if the person who stole the phone made a call from that phone, how am I suppose to know the number? I asked if I could give the IMEI number to receive my blacklist number but she was unable to assist me!!! I need a blacklist number today!!! PLEASE ASSIST!!! HOW CAN THEY NOT HELP IF YOU DONT KNOW THE LAST NUMBER DAILED????