From the stand point of a telco provider, they will charge anyone who makes the idd call. Call barring is available to prevent overseas call being made from one's number. I was also told by one provider (name withheld) that these China calls can charge up to usd2.70 per min plus gst. My loses so far range from 2cents to xxcents. Can't control my bad habbit of not looking at a phone to pick up a line or to call back. Fortunately, my loses so far does not amount to more than a whopper meal.
So, there is no real solution and not one country can stop another from such fraud. Don't forget, telcos also want to make a living and it is near impossible to do policing since their role is only to make some $ by connecting calls and sending data signals. Who knows, there might be some bad guys in Singapore doing the same thing to overseas' victims to bring more wealth to the local economy.
Maybe we should just hang up and move on.