Unable to progress 'Vessel of Hatred' for 'Slay the colossus' quest. How would i create a support ticket for this?

I have been trying to complete the Vessel of hatred quest line and am upto ‘Tenents of depravity’ but the quest would not progress for ‘slay the colossus’, i read that abandoning the quest and restarting it is a way to fix this, which i did but now i cannot find how to reacquire the quest. these both seem like potential bugs. Is there a way to fix this issue?