How do I stop getting unwanted calendar events?

I Keep getting spam calendar events. I have an icloud.com email and for some reason I keep getting these unwanted event invites. No matter how many times I report them, they just keep coming back. These events normally include a very suggestive title and a link. I've never clicked on the the link so I don't know where it goes.

Apples website only shows how to delete/report the invite. How do I stop the invites from happening? Is there a way to block anyone outside of my contact list from inviting me to an event?

I should clarify these events pop up in my calendar inbox and on my calendar itself. I do not get emails notify me of these created events.