Solved

I think that I cannot be fixed, same thing happened to me, in quest "boethiah's calling", when I killed the whole clan there, and manage to invoke Boethiah, but quest didn't finished, I must admit there are musch bugs in the quest's for sure...

Did you try talking to Nazir?

He just gave the usual "money making contracts", nothing about the main quest.

I think that you have to make the "money making contracts" for having new main quests.

I had all kinds of issues with the DB quest lines. I finally gave up and started over. 2nd time through for my thief, and his sneak isn't going up as I'd hoped. My weapons stink and I switched to Leather Armor. I'm going back to glass armor, even though it looks terrible for a thief/Rogue character. It just seemed to work better.

No i think you have broken the quest because it happened to me to when i just went ahead and revealed sibbie's plan to steal frost to the maven the quest just got stuck in active quests no more going on . and in that boethia's quest you need those cultists because you should fight them to prove your worth to her . i think you have done sth that has broken the quest . because i got to the end of the dark brotherhood's quests.(I haven't used patches)

bump, new issue