[matrix_smq]

You have to use

Код:

ID = ReturnUser(cmdtext[6]);

And at the

Код:

format(str, 64, "%s has been banned from the server for: %s", pName,rest);

Take the ",rest" out.
Here is the code, i think it should work

pawn Код:

else if(strcmp(cmdtext, "/ban", true, 5)==0)
{
  if(!IsPlayerAdmin(playerid)) return 0;
  if(!strlen(cmdtext[6]))
  {
    SendClientMessage(playerid, COLOR_ORED, "Usage: /ban [playerid] [reason]");
    return 1;
  }
  new ID = ReturnUser(cmdtext[6]);
  new pName[24], str[64];
  if(IsPlayerConnected(ID))
  {
    GetPlayerName(ID, pName, 24);
    format(str, 64, "%s has been banned from the server for: ", pName);
    SendClientMessageToAll(COLOR_ORED, str);
    print("Player banned");
    Ban(ID);
  }
  return 1;
}