[Konstantinos]

The command you have at the moment, it bans online users only. You should make a ban command for offline players too and then check if the banned name is "James_Willowfield", then ban otherwise if the player exists to your files/database then ban him/her.

Or you can use what the user above said, but editing the parameters because it'll give errors.

pawn Код:

new 
    playername[ MAX_PLAYER_NAME]
;
GetPlayerName(giveplayerid, playername, MAX_PLAYER_NAME);

if(!strcmp(playername, "James_Willowfield"))
{
    // code;
}