I killed Madanach just before exiting the mine and got the note from him. However, I did not read the note. I exited the mine and had a drawn-out, exhausting battle with the Forsworn whom I finally managed to kill after about 9-10 tries.
I then looked at the quest status and it require me to read the note from Madanach. I read the note. The next goal is to exit the Cidhna mine... which I cannot do, because when I get back to Cidhna mine, the quest marker points at the far end of the mine, which I cannot reach. There is Urzoga gra-Shugurz (the Orc prison warden) with a couple of Silver-Blood Guards. The place has no means to get to the prison cells (where the marker points to). There is a chain with a barred window in front, but there is no option to activate or pull the chain.
I'm stuck here. Can anyone tell me how to complete the quest?