How to see messages from a blocked number on an iPhone, and filter messages from unknown senders

You can't see blocked messages from a number you've blocked on an iPhone, so you'll have to unblock that number if you want ...

Here's what happens when you block someone's number on your iPhone

When you block someone's number on your iPhone, that number can't call, text, or FaceTime you. It won't affect third-party apps like WhatsApp, though.