authenticity cards

I went to the Prada boutique here and they wouldn't authenticate the bag for me. They looked at it and said it "looks good", but wouldn't give me a definite answer because it's against their policy.

Prada generally doesn't authenticate. There's a lot of expertise both here and on the ebay community board. If you post photos (or, if it's ebay, a link to the listing), you'll get some feedback. I wouldn't rely on the cards. It's the bag that's important. But, there are a lot of counterfeit cards, so you should also post photos of the cards because there are sometimes some telltale signs that indicate they are counterfeit there too.