Reset stolen iPhone

You did the right thing. If it is in Lost mode no one can use your phone. You can also erase it, but if you do you can’t track it (which probably doesn’t matter, because you aren’t going to get it back, anyway).

Just don’t remove it from your account, and don’t fall for any phishing scams like this one: 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.