Try to email support Here or click the 'Contact Us' button on the bottom right of the forum page, it should look like this. They should get back to you soon enough.
Since Mineverse is set on your Username and not you UUID, you cant change it unless you change your name of a moderator breaks it for you (if they can). Tbh Username is soooo old and they should change to UUID.
Like what she said get a mod because I believe they are the ones with the permission to do the stuff or admin if you can find one hope you can get it back
Is this resolved? Has a moderator broken the signs for you, or have you changed your name back? If not, email [email protected] Or ask a moderator.