Do you think I can get My iphone back?

I lost my Iphone In whistler british columbia and A few months later I checked find my iphone and I saw It online! I know someone is using it because the location and battery level changes and my phone had no password… There was no sensitive stuff and its basically used as an I pod because the sim card was deactivated

I feel like turning it to lost mode would just anger them and not want to send it back Should I do it and would they even send it back?

Most of the possible outcomes leave you with no phone. If you wish to deny the finder his prize, then you lock it down and hope they return it. If you don't care, erase it and release the lock. In any case, you DID change your Apple ID password and others, right?

If you have the location, go there and get it. You can also get help from the cops.