Dark Brotherhood side contract bug

[Kaos1391]

So I started the Dark Brotherhood quest line. When going to Nazir and he gives you the first set of contracts. I was given only two contract when the dialog said 3, I completed the two and handed them in. Then after being told I was the listener and Astrid told me to see Nazir for more contracts. I asked him. To which he responded "You haven't finished the last ones I gave you." But the third one is not there. I know its to kill Beitild but I can't find him anywhere. Is this a bug? I have tried to reset the quest and tried to make it complete but nothing has worked. What can I do to make it work again. It looks like I can't continue on the Brotherhood questline without it. Anyone have this bug too?