You see the following ad for a used mobile phone on an online marketplace: "My smartphone works perfectly, but I want to upgrade to a newer model. Selling for $100 OBO.”

You meet the seller in a parking lot outside the store of a service provider you plan to use. You hand over the cash, and she hands over the phone.

Inside the store, the service provider has bad news—he cannot activate your phone, because it has been reported stolen.

Does this represent a case of fraud?

Yes. The seller lied about the phone when she claimed it was hers.
Yes. The seller lied about the phone when she said it “works perfectly.”
No, because it is up to you to be aware that sellers may lie.
No, because the seller met you as promised and did not charge more than advertised.