Final Trial quest bug can't continue game.



I am playing witcher 3 on ps4 and i am about 35-40 hours in and when i try to do the quest final trial it tells me to find lambert but he is not there. I spoke to him prior and he asked if i wanted to start the quest i said i would come back later. I return to the exact same spot and it says he is below but there is no way to get below so i think he has fallen through the map. I really want to continue playing witcher 3 but i cant till this is fixed. I have tried fast traveling, loading a older save, meditating but nothing seems to work. Please help i have seen other users report this bug to but i didnt see anyone post it here so please help us.