Blocking stolen iPhone

Hello ~ We are users just like you are so while we cannot help you in that regard… here are some steps you can take:

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

Use the Find My app to locate a missing device or item - Apple ...

~Katana-San~

Apple does not block stolen phones. Apple doesn't get involved in lost or stolen devices at all.

Contact your cellular provider to ask if they have the ability to blacklist the phone and read this link for what to do if your phone is stolen --> If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support