My stolen iPhone

Sorry your iPhone was stolen. Apple offers this advice when an iPhone is lost or stolen. You should at least be able to so some of the steps.

If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support

You can’t track it when it is offline. But even if you could, what would you do about it? Confront the thief? People have been murdered doing that. Assume that you are not going to recover the phone. Most likely it’s on its way to Shenzhen China, where there are huge businesses that prepare iPhones (and other smartphones) for resale. Contact your carrier and have them blacklist it, and never remove it from your account; that will keep Activation Lock enabled thus thwarting any attempt to resell it.

Also, beware of a common phishing scam: You may get a text or email from “Apple” or “Apple Security” (or sometimes “Police”) saying your phone has been found and to click on a link to see its location. This is NEVER from Apple or from law enforcement; it is from the thief or fence to steal your Apple ID and identity. Delete any such message without responding to it. Apple never gets involved in lost or stolen devices→Avoid phishing emails, fake ‘virus‘ alerts, phony support calls, and other scams