I reset my iPhone and my phone doesn't read SIM cards, and on the activation screen you need a SIM card to get pass it , I need somebody's help with getting past the activation screen , PLEASE I need my phone back ,

I Just bought a SIM card for my iPhone 5 and I put it in my phone and it didn't read it, so I put it in my sister's iPhone and it worked. I called the man that runs my phone plan, and he said to reset my whole iPhone, so I did and my iPhone doesn't read sim cards so I can't get past the activation screen, I really need to get back into my iPhone , can somebody please help? Or tell me w my iPhone isn't reading SIM cards! PLEASE I REALLY NERD