I recieved an email which tells I'm the lucky winner of Yahoo! luckydraw. How can I confirm with yahoo?

I recieved an email from postmasterMailcongratulates1@yahoo.co.uk containing some codes with yahoo lotto logo and ... and some numbers for yahoo office in London. So I trusted because it was from yahoo and called them. But after one week they asked me to transfer 850 British Pounds Sterlling (postbank costs) to send me 800,000 Pounds. I don't know how can I trust because I couldn't contact yahoo by mail.
I recieved an email which tells I'm the lucky winner of Yahoo! luckydraw. How can I confirm with yahoo?
Don't trust them. You need an intermediary you can trust. Send 1,000 pounds to me. I will pay the 850 pounds and keep the rest for my fee. I will protect you from the problems.





Really - why do you think a random person would give you a large amount of money for nothing?
Reply:It's a scam
Reply:Please delete it immediately. No one in this world will give you money without reason. God bless you.
Reply:Don't do it! It is a scam!! Big time!
Reply:its all bullshit...........do not try any thing .just tell them send you the balance after deducting 850
Reply:If you are willing to fork over money for that scam, I can give you a way better deal in America. I can sell you the Brooklyn Bridge for way less...