Instant CheckMate.com Improper charge to credit card California

I found a charge on my credit card that was not put on there by me.  When I called the company they said they would identify the account that had been opened fraudulant.  The problem is that they said they would only refund 50% of hte money to the dredit card untill I raised a lot of he**.  They did not want to turn over the information of the email address of the person that opened the account without the same.  These people are a real scam artist knowing that it was afradulant account & still only wanting to refund 1/2 of the money.