Upgraded to WP 4.5 and now my site is broken

Hi

I upgraded a site to 4.5 this afternoon and now I can’t get in, not even to the admin panel. Before I clicked upgrade it did say that there might be some downtime but after reading through threads on the same issue I figure that there is a serious problem.

I have tried three different browsers and cleared my browser cache and cookies and nothing has changed. To make matters worse, I currently don’t have the login to the FTP client as I didn’t set up the hosting account and I can’t get hold of the guy who did. Is there any way to just get the site running again without going through FTP???

Panic mode here.

URL : https://www.hotelselvazul.com

Thanks in advance.