If someone is calling you about check fraud, and if she calls back saying you can pay a "fine" to take care of the matter, it's a certainty she's a scammer.  

If it's a debt she's trying to collect, always demand that the caller send via USPS mail a debt validation letter proving you owe the alleged debt and that they are legally able to claim and collect said alleged debt in your state.  Any caller who refuses to send you information proving you owe a debt is in violation of the FDCPA.

A woman called about a fraud check.  What fraud check? The telephone number they left is 1-888-338-1540 extension 103.  Who is this?

I received a message about a fraud check.  Who is this?  What company is this?