Essence of the Artist Quest-Bug

Hello,
I have an issue with the Esscence of the Artist Quest ind Act 7.
I was playing a Heiro-Righteous Fire build and went to the Chamber of sins level 1 to activate the Map device. I entered the Map and everything was going pretty normal until i got to Maligaro's Sanctum. When i defeated him there was a little bit of a lagg as Sin appeared, but then he just stood there without an exclamation mark above his head. His talking options also were no more than "Goodbye".
I thought nothing too much of it at that time scine i didn't know what was supposed to happen, so i left the area and keept on playing until i got to Act 8 with the Quest still in the state "Travel to Maligaro's Sanctum".
But i can't travel there anymore because the Map device can't be used and i don't have the Map.

I would like this problem to be fixed please.
Thanks.