What has hijacked my mobile Wordpress site?

If you go to blog.kenguie.com on your mobile browser, there seems to be a "win an iphone7" ad that has hijacked my site. It pushes you to its ad site and there seems to be no way back.

I've tried updating everything and I only use plugins I'd say I'd need.

Is there any way to find out why this is happening and how to stop it?

Thanks!

via Chebli Mohamed