It's widely discussed in the IS forums, including an explanation.

Yes, I got the same issue. I don't know the IS forums, so if someone knows the reason I'd appreciate if they could post it here as well. Thanks!

How about I explain you how to access the IS forum then?

So you're on the Getty ESP site and are looking at your views/interactions and see the message "It appears you have no activity in the last 30 days."
Right?
At the top-right of the page: click "Contributor Community". When arrived at that page: click "Forum" in the left hand navigation.
That's it.

In the forum "IStock Help", there's a topic "iStock ISSUES": it gives the latest info on things that currently work and don't work, and when they're expected to be fixed.

OK, so now for your question: the View/Interaction statistics have been broken for the last few weeks, and yesterday iStock has managed to bring them back.
So try again now: you should be able to see them.

I'm personally glad they are back. Now that I'm uploading more, it's great to get some early feedback to see which of the newer work is getting attention.
Happy uploading!