The account associated with "Mogarg" on the PvP server has never been banned. Most likely you tried to log in with an incorrect password too many times, triggering an automatic lockout to avoid hacking attacks.
Wait 30 minutes to one hour and try again. If you still have the wrong password, you can change it by going to https://en.nostalrius.org/password - you will need your account name and the E-mail address you used to register the account.