I've been trying to validate my account through email for the past 3 years basically and i was wondering when you were going to fix this issue. Now you must be thinking why haven't i brought this up before well i did but not through the thread. I think it was through here and email and also i want to change my username that is the main reason.

Is your email address valid?
Have you checked fully in the inbox folder and / or spam folder of your email?

try to contact some mod ;-;

Like Leonaki suggested, the email you've been sending validation codes to may not be the right email.
I suggest you ask to get your email changed through the contact form which you can find here.

You should get an email response within two weeks, and if not, contact a sentinel and they will contact an admin directly for you.