Yes, unfortunately, I have seen copper plated/bonded onto pans made of other metals. I was even snookered once myself, although I share in the blame--I was trying to score a huge bargain where the seller had not given the pan's WEIGHT.
jljohn is right: it would help if you posted not only a photo, but gave dimensions and weight. We copper nuts develop the ability to "smell" pans that are suspicious. Weight is a really important clue, and sometimes our eyes alone aren't enough!
The good news is that eBay should allow you to return the pan for a refund if the seller misrepresented that it was solid copper (Don't *necessarily* assume the seller is a fraud--s/he may just be ignorant).