<prompt> Human: Im not sure if this is the right place to ask for advice regarding this. Im a college student and dont really have anyone else around to come to for help. These people have my address, Im not sure how to proceed.This all started last month, when I posted an ad on Craigslist trying to sell my bike. A few days later, a guy contacted me via email and said he wanted to buy it for his son, but he was away from town so he would send me a check instead of paying by cash. He said the check would arrive in a few days, so I waited.It took him nearly 3 weeks to send the check, and he sent it in a big package with a tracking number, which was very strange. He also contacted me 2 days before the check arrived and said it would be for over 1000 I only sold my bike for 250, and that the extra would be for a shipping company that would come pick up the bike for him.When the check arrived, it looked extremely suspicious. The address on the envelope was from one company in Arizona, the address on the check was from a resort in Florida, and the number he gave me was from California, so it seemed extremely fishy. I showed the check to my friend who works at a bank, and he said its fake because part of the print was very pixelated, and the signature was poorly printed on and very blurry.I texted the guy, saying I did not cash the check and has thrown it away, so he can cancel the payment. I then blocked his number and email address.Two weeks later today, someone claiming theyre an FBI agent is emailing and texting me saying hes received complains from the guy, then threatened to carry out regular duty if I dont send a refund.I know that this FBI agent is fake as well, and theyre just trying to scam me into paying the money, but how do I handle this situation? Do I just ignore them? Is there someone I should contact?Edit: Thanks so much for the advices, everyone. Sorry if I seemed clueless, Im not from the US and only moved here last year for university. Ill take more precautions in the future.  <response>: Craigslist has warnings posted all over the site and on every post about this scam.Just ignore them.And next time, read the warnings. 