or you can do the following to unban an account
don't know if it actually works though
1.Open the registry editor. -> Windows + R then type in 'regedit' and press enter.
2.Navigate to this registry key: HKEY_CURRENT_USER\Software\Epic Games\Unreal Engine\Identifiers
3.Delete the folder
4.Restart the entire Epic Games Client, not just the game. --> This should regenerate the registry keys with new values, thus unbanning your account.
Hope this helps!
Note: I did not discover this fix. I'm posting it here for others who are having problems