Recovered lost iPhone 5

Hey guys,

I've had an interesting day and was hoping someone could help.

I left my iPhone at a store earlier today when looking at an item. I went back (once I realized) about 15 minutes later to the same spot and the phone was gone and no one at the store had heard or seen anthing.

Well, after hours of agonizing, I checked on craigslist and found what looked to be an exact match of my iphone for sale. I called the seller, acting like an interested buyer, met the person (with a couple of friends) and realized that in fact, it was my phone. After confronting him about this being my iPhone, he gave in really quickly...knowing he was busted...crazy story. He gave back the iPhone and sim card.

So, upon receiving my phone, everything had been restored to factory settings. I got home and tried to insert the SIM Card, but it is not recognizing the SIM. I am wondering if you guys can advise. Can I go to an Apple store and get a new SIM if everything is backed up?

Thanks for your help.

-C