Spam on iMessage - What are my options?

A person unknown to me got hold of my Apple ID (email) which is registered with iMessage. While as I understand, there should be no harm in some stranger having access to my email address (apart from the possibility of receiving spam emails).

However, what's concerning me is that this person is sending me a truck-load of messages on iMessage. He/She is also constantly trying to reach me via FaceTime Audio/Video.

I have politely requested them to state the intent of communication. However, the person appears to be engaging in irrelevant chatter.

After repeatedly requesting to stop it, I pulled the plug by blocking the Apple ID. However, the person retaliated by creating a new Apple ID and starting all over again.

I am quite bothered by the unnecessary communication which I find to be distracting. I have blocked the second Apple ID too and, in response, I have started receiving the communication from a yet another Apple ID.

What official options do I have to stop this? Will reporting the Apple ID(s) in question enable Apple to take actions which can prevent this further?

According to Apple: "If you get an iMessage from someone who's not saved in your Contacts, you'll see a Report Junk link under the message." You then have to block the sender if you want to stop getting messages from them.

But since you are asking the question I'm guessing that isn't showing up. And since the perpetrator is jumping to new Apple IDs every time you block them I don't know how useful it would be.

If you do end up seeing the "Report Junk" link, maybe use it and don't block them, just mute the thread, reporting it every chance you get?