I don't know what yahoo is up to or if he is lying or not but always assume that your money is gone when you donate money to somebody. It is meaningless to cry now.

Let's say you were scammed by yahoo, what you can do about it? Nothing other than giving him a red trust rating/creating a flag. He already said he is not giving it back.

Now go cry in a corner.

Every day people come up with all kinds of excuses to borrow money without a collateral in this forum. You ignore them don't you? Do you get impressed by their story and send money every time you read a sad story? Why did you do it this time?