You are responsible for writing down the email addresses you use to sign up for accounts on websites, you are responsible for all the information you use to sign up on a website. You posted their terms on dormant accounts and the answer is simple, you screwed up and lost access to the email address or whatever, so it is your own fault.

It has been 5 years as well, and you're likely only worried about it hoping that they or someone can help you because the btc price is much higher then it was years ago.

My advice, keep notes somewhere when signing up for websites. Write stuff down and be responsible. Don't expect a website to fix your mistakes.