I ordered a laptop from a seller on eBay a few years ago.

Sent money by certified check, then waited. And waited.

Occasional contact by e-mail, with repeated promises to mail the computer. No ability to call the person who sold the computer.

I started contacting fellow bidders, and no one had received their computers. Once I started putting the pressure on the seller, he did return the money. He was indicted later.

The story was posted (not by me) on www.laptopscam.com

So, my advice is this: You are not being paranoid. Notify your credit card company for possible fraud. It was probably too good to be true!