Fishman Fishbowl LP Internet scam. overpayed too much and expected return of difference Atlanta Georgia

I posted on a web site to sell a set of atv tires. Later the week that I posted on the web site, I received an e-mail from a "Matt Wu" saying that he wanted to buy the tires. I told the buyer that the tires were sold to DO NOT send payment. The payment arrived next day air yesterday which was about 3 weeks after I told him not to send the payment. The tires are already sold to a local buyer for $250 which was my original asking price. The check from Fishman Fishbowls LP was for $2500. Not a typo. The check was made out for two thousand five hundred dollars. The company wants me to cash the check at my bank, deposit "my" $250, and then send them whatever is left in cash. I have not and am not cashing the check.

Coot23
Lanett, Alabama
U.S.A.