Okay, I can tell you already that this is a scam. Not even talking about the size of the loan, just concider this:

How can you say that you want to pay 20% interest in 6 months (which comes down to 40% yearly), and also state that you think that the bank interest is too high? Interest in a bank is usually 5-8% these days, and you think that's too high compared to the 40% you're offering? Just leave, scammer.