Maybe you can wait and email them next week, it'll be a month since your last email by then. It is confusing because usually you get pre arrivals when you've passed eligibility which would mean you wouldn't need an interview, your relationship is genuine. Unless there was something in the background check, but I don't know if they would schedule you for an interview for that. I know how you feel, their emails are so short and you hardly get any information from them. It would make you feel better if they could explain things a little better. I think you mentioned before that you had ordered your notes right? so hopefully you'll received those soon and you will get more info from that hopefully. Try calling your MP, see what he can do, try to go over your lawyer maybe you can speed things a little bit without him.