I suggest to have your MP implicated in your file to clear this up. This is stupid from them to ask you to wait for their letter and then reply to their error.
Is your application linked? if not, they likely sent it via regular mail. When they sent a batch mail in June 2016, we received a letter in early July, but the date on the letter was June 20th. So, if it is in the regular mail, it might be normal that you did not receive it yet, for some reason it takes several days before actually leaving their office; but you should get it very soon.
Also, did you ordered your GCMS notes in the past? If yes, make sure there is no typos in your email address. It happened to me (the sponsor), they did a typo in my email. I ordered my GCMS notes in November, got them in December 2016 and realized their mistake, sent a correction via CSE the next day.
Gloria, I sincerely wish you to get good news very soon!