Man sent 2000 dollar check and I ripped it up thinking it was a scam is it illigal?

Hi I was selling busch garden tickets on craigslist.com that I got full price and was selling them for 50 dollars. (origonal price $61) This guy said he would pay an extra $20 if I held one of them. that is $70 right there. That didn't seem right to me why pay more than what you can get. Then he sent me a check through UPS for a total of $2000 he said that it was a mistake that he wrote it for that amount. How would you make that big of a mistake? So I wripped it up and said heck with it. I emailed him saying I wripped up the checks and said I didn't trust it. He emailed me back saying if he doesn't get the rest of the money he would contact the FBI. Is what I did illigal would you do the same thing?