Can't log with steam account

It is simple:
I can log here on the website and view my character with my STEAM account.

When I open the game it asks me for an EMAIL and a PASSWORD I dont know.

I can't change the email or the password on this website since it is asking me for a password I DONT KNOW.

I can't log in the game using steam credentials...

I'm pretty fuc**ed.

What do I do?

Thanks!