I've been hacked and can't access my dashboard

So my website was recently hacked… bad.
I’ve wiped everything out on my server and plan to rebuild from my back-up. However, the hackers have changed the password to my dashboard and the contact email address to my wordpress Dashboard. So I can’t even click on “Forgot password” and have them email the new one to me because it won’t be sent to my email address.
Any ideas on what to do?