Sorry to burst your bubble, but I had to do the same thing when my account was compromised a couple of years ago. Someone thought it was a nice idea to try and withdraw $500 from my checking account. I had never done business with whoever it was, and I not only had to file a police report, but be interviewed by a detective. They do this to weed out those who want to claim fraud, but have got the goods and just don't want to pay for it.
Note: I am not saying this is what you're doing. Please keep that in mind before you snark at me or anyone else.