Lost ipod gets stolen?!Help!?

Okay so I went with my mom to Macy's , and asI was getting out of the car I guess I dropped my ipod touch on the ground but didnt know. After we went home I still didnt know it was missing. Then I remembered, "where is my ipod"!!! I went looking for it everywhere, even my mom went back and looked around macys, but had no luck.Then we thought maybe its in the house and it will soon pop up. After a few hours, someone called, and said " Did you lose an I pod touch at Macys? and i said extremely happy," OH MY GODD, YES, THANK YOU SOMUCH" and he replies "yea well im keeping it *****" and hung up. D: I dont know how he got my number, unless he got through my passcode... And I have the mobileme thing and I tried wiping it but it keeps saying pending.. And we also filed a police report, but theres not much they can do. And I know its just an Ipod but I spent $300 so Im taking this very seriously and want to get it back or find the guy. Thanks(: