Complaint Review: Walmart Services Group

I receive mail a letter from Corres CTA Madrid, Spain, with no return address. When I opened it, it was a photocopied letter from Walmart Services Group at 702 8th Street, Bentonville, Arkansas 72716. The letter encloed a check for $1970.00 and the letter stated that they were giving me a chance to become a "Mystery Shopper". This was unsolicited. It seemed very suspicious based on the instructions, so I went online to check the status of the group. I pulled up numerous reports against this group. I found several reports of the same experience from others Can someone please track these people before they end up scamming more money from the U.S.? Thank you!