Hello,
If you have a phone number or security email linked to your account, or know your security questions, you can recover it through the account recovery tool or by creating a CS ticket in game or in your user center. Here are the links to the two platforms you may use. Please keep in mind that recovering your account by creating a ticket will require more stringent information checks.
If you do not have any of this, you can attempt an appeal through the Customer Support ticketing system.
Appeal:
https://profile.oasgames.com/web/reset-password/get-user-name?lang=en-us
Customer Support:
https://support-center.oasgames.com/