You can call them and ask if it has been approved yet. That is what i do i call them as they give a reference number. I mean call the office that you went to for the extension. Maybe call on Wednesday then you can go on Thursday
Once again i think it depends what immigration office you have to visit. When i do it i make 3 copies of everything, so there is no problem. I also hand draw the map of how to get to immigration from my house. Never had a problem, but as i said it depends on the office.