It may very well be a scam. However, there are programs and schools in China that pay around what was offered - particularly ones offering overseas diplomas. Ask yourself - Are you qualified to teach the position being offered to you? I'm meaning - Are you a certified teacher (with a degree in Education, not a TESL certificate) or do you have an advanced degree in English or Linguistics? How much teaching experience do you have?

Who is David Hu and what is his position in the school? I'm looking at the website and found a "Hu Chen" who works as "General Affairs Driector." It may be him. How did you find and apply for the position?

Ask questions. Getting more info doesn't mean you need to commit. If it starts to sound even more fishy than it does now, all you've wasted is time. Be careful of the "immediacy" of the position, that's how people get tricked into accepting a position without signing a contract ("We don't have enough time to send it to you. You can sign it when you get here.") or coming in on the wrong visa.