Stolen iphone and sim card q?

Someone stole my iphone, the sim card is still in and activated. I called atnt to try to get my phone back but they didn'y help much. I'm thinking of going to the cops tomorrow.

But the sim ist still in, they are getting my text and reading my text. So they must had kept the sim in and restored my phone to take the passcode off. So they must had put their email information, in the beginning so my question is with the phone activated and the sim in can I find out who stole my phone? Like someone with my service provider can they find out who registered my iphone?

since in the beginning of starting up a new or restored iphone it asks you for your name and email… Can I have access to that email since my sim card is in? And activated?