Service Performance Group Inc, Mailed me a letter with a bogus check to hire me as a "secret shopper" Duluth Georgia

In response to a multitude of internet employment opportunities, I received a letter from Service Performance Group with a check for $1310.00 US enclosed. The letter offered me the opportunity to be a "secret shopper" at Walmart; as a trainee to start with two separate assignments. First I was to deposit the check in my bank account which I did. I examined the check closely for security features and watermarks etc. The bank accepted the check and accredited it to my account. I went to do the first assignment which was to send via walmart2walmart money center $800.00 to Walmart in Atlanta. The second assignment was for me to spend $100.00 as I wished for myself. Plus the remaining $400.00 was my pay for doing the two assignments. So I first went to transfer the $800.00 with $9.50 as a fee for the transfer to Atlanta. The transaction was declined. I contacted my bank and went back and forth with my bank and Walmart. Finally my bank froze my account and the transfer was denied. The bank fraud department associate told me that I may have to pay the $172.66 that I spent of my supposed $400.00 pay plus 4 NSF charges totaling $140.00 AND I may be responsible to repay the $1310.00 bad check for putting it in the bank though the bank witheld the deposited check for 3 days and then credited it to my account as valid. BEWARE.