LOST ITEM NOT RETURNED!!!

UBER Drivers are ******* these days hey. I left my phone in an uber and the driver didn't answer it when i called it. i called as he was driving off but still he didnt answer it. it was on the front seat. i contacted uber and the driver told uber he didn't have my phone. uber is telling me to go to the police and the police need the serial number of the phone i bought a year ago. i don't have the serial number anymore