Can hash be found using a nickname?

[BUK__]

The question is pretty much the subject. Recently i ran into a problem. I am banned on a certain server under another hash id. I have appealed and now should be unbanned but i keep getting "You have been kicked, reason: account verification failed". I assume that the reason is my old hash. I guess it is still banned and now i need to know if I can do anything about it.