Need help recovering account

Hello, very old player making a comeback, well at least trying to, i forgot the username of the account i used to play in, but i have no email on it because this account is from the time were accounts were automatically created. I can provide proof of ownership if needed. By the way, we are talking about a really old account, think around 2010-2011, last login from around late 2013. Any sort of help will be apretiated.