Complaint Review: American Cash Rewards/Robert Sherman

I was contacted by a Mr. Robert Sherman concerning a sweepstakes i had supposedly won second place and had won $500,000 and a 2013 Mercedes Benz. i was instructed to go to Wal-Mart and purchase a Green Dot Money Pak and load it with $390.00. At first I was excited to think that I had won some sweepstakes I had entered thru the mail. Things did not start to add up when I was told the first time that all they needed was the cash register reciept number to confirm that I had purchased the card. He then changed it saying they needed the card number to "GOLD STAMP" everything to complete delivery.I told him I had no problem getting the card but I would not give anyone the card number over the phone where they would be able to draw the money without me having anything eithr parked in front of my residence or the cashiers checkin hand. my wife and i had checked out American Cash Rewards on the internet and saw all the reports. there was no way I was giving anyone any card number. He also tried to get me to put it on a credit card that he said i had. I had no card of that sort. I questioned Mr. Sherman about where my winnings were being held and I would Come and pick them up and give them the card number at thsat time since it was supposed to have been shipped from Las Vegas, Nevada to Kansas already. He said that was not possible. I finally got upset enough to tell him to get *&%$ed!