My Apple-id want me login with an old non existent e-mailadress

I´ve used the sam Apple-id for many years and I have changed the primary e-mailadress twice since the beginning and the original adress doesn't exist any more. Logging in to my iCloud using my apple-id isn't any problem on my iPhone, iPad or my Mcbook. But yesterday I started up my iMac after a long time not using it and I upgraded the os to Yosemite. Now it wants me to log in to iCloud using my old non-existent emailadress. And when I try, it says something like "You can't log in because your account has been inactivated by security reasons." And then it suggests me to reset the password at http://iforgt.apple.com.

To reset your password you have to recieve an email on how to reset the password. But since the email-adress doesn't exist any more thats not an option. It then suggests me to answer my security question and first you have to enter your birthdate but when I do that Apple says it doesn't match with the birthdata I've entered 10 years ago. 🙂

So, how do I solve the problem?

/Fredrik Meuller