S Logistics Group, LLC Mystery Shopper Scam Internet

I received a check today in the mail. It looks legit in the amount of $1999.20. For a proposed mystery shopping position. I have checked all of the internet for this supposed business that claims that over 800,000 people are part of. I have called the number that is on the letter for hours now and it is either busy or states that the number was dialed incorrectly. When I reverse look up the address it is coming back as a Rehabilitation/Therapy Facility. I checked the BBB and it has no record of this company. The letter states that I am to deposit this check into my account then deduct my first weeks pay at $350 and the remainder of the check is for the mystery shop. This is a scam of some sort-what they are doing I am not sure but it is not right. If you cannot reach a company by their phone number and they are supposedly a legit company with that many members-something is wrong. Do not cash this check-it is not written on an actual account-it will bounce and you will be responsible.