I found a phone! What should I do next?

I found a hand phone when I took a cab.

My first instinct was to give it to the taxi driver. But what the point, the owner dont even know the taxi number. So I decided to keep it.

After the ride, I went through the phone a found two interesting things.
The keys were worn out but the sms inbox is full of unread 4D results.Secondly, the phonebook contain 5 contacts only and the names in chinese characters.
I really dont know how to contact owner.

I wished to return the phone to the owner but the owner never called back. I waited until the lines were cut off.

So what is the next best action?