What AM I to Do.. I just been Scam by RichField Lending Group?

Okay I recieved a phone call from Kathy Foster. Saying I was approved for 20,000. So she faxed over all the doents. My mom and I was asking a bunch of questions about this. So we both thought okay it seems legit. Kathy Foster said that before receving the loan, I would have to put down some collateral. It was $2000.00. Then I will recieved the funds in my account the next day. But i didn't, I recieved a phone called from Steve saying I had to put an additional $2000.00 for me to receive my loan. But this $2000.00 I said No. I want my refund back, Steve says that I won't get a refund back until Oct. 17,2008. What am I to do??? Please if anyone knows what i should do please let me know..!!!!