What should I do they didn't send me iphone?

Hay please help me. I had seen a ads of iPhone and I contact that person. They told me to send the money from Western union and I send it now they didn't send me an iPhone. Big problem is I'm in Hong Kong and he is in United Kingdom so what should I do? Should I complain to police or what?

Get there correct business and see if its real
I hate to say this but it sounds like you have been scammed

Never again use western union
Always a credit card so you are protected
Yes call the authorities.

Oh my gosh, that sucks.

Next time please do a deeper research on the person selling the iPhones to see if they're legit. Personally I wouldn't recommend buying an iPhone online (unless you purchase from the Apple store). Hate to say this but you might have just been scammed.

. Or on a positive note, the phone might have just been delayed. Try contacting the person, and if he/she isn't replying, then you know you've been scammed.

You can file a police report but they can't get your money back. This would be considered a civil matter i the UK and the seller (if they are actually IN the UK and not just giving a fake UK address) knows that nobody is going to pay to fly to the UK, stay in a hotel and pay the court fees to sue them in civil court to recoup £300 or whatever they lost
Legitimate sellers do not ask for Western Union payments - they accept Paypal or credit cards
And why would someone in Hong Kong buy a phone in the UK where they cost more? Why do you think British tourists buy their electronics and phones in Asia -- because they are about 20-30% cheaper than in the UK