Act 2 Ending Quest Bug

Chose the path to eliminate the bandits, and i was in a party with a friend i lost my amulet and my friend had his he implemented his amulet into the chamber and the quest started Boss dies and we go to finish the act by leaving into the portal friend with the amulet passed through and now i can not.

Tried these below:
1: Restarted Game
2: Re Ran the entire sequence with dungeon reset and without
3: Tried to obtain missing amulet from the bandits doesn't drop.
I can not play the cruel difficulty because of this.