lock iphone

They would not be able to remove your Apple ID unless the password and passcode was given to them. Those are the 2 pieces of information that will allow anyone to take control of your phone. Please provide more information on how they were able to obtain this information and how you know their Apple ID is logged into it.

If you think your Apple ID has been compromised - Apple Support

If their ID is logged into it then effectively ownership of the device has passed onto them unless you can recover the device and you have a receipt of purchase for when you bought it from Apple.

How do you know they have their ID logged into the phone? This is not information that would be communicated to you.

This support article has a list of things to do if your iPhone, iPad, or iPod touch is lost or stolen. --> If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support

- The Find My service described in the article is the only recovery feature Apple offers. It must be set up before the device is lost.