Can't access my account

My account is over 10 years old and Associated to an email provider that no longer exists. I want to login on a new phone but I can't because I don't remember its passwords and the only option I have for password changing is via the email that is available no more and I've never associated it to a phone number either, so how can I access my account? Bear in mind I still have access to it in my old phone, but it gives me no option of changing either the email or phone number.