i can't get through this dungeon. the enemies ether kill me or i never get anywhere. if you know what to do in this dungeon plz post here and also ping it to me

Your pets' gears are too weak. You'd need at least epic gears and some strong restore elixirs which you can get from the mission satchels (lv 45 and 50) to clear the Dungeon of Forsaken IMHO. Also make sure you choose relic damage that fit your proficiency. If your proficiency are air, earth, or water, choose physical damage relic, otherwise choose magical damage relic.
If you don't know how to set up your battle team, you can see this useful guide by Divinis here. I also put my team set up there, but mine is specifically for fighting multiple enemies, so Divinis's set up might be more useful than mine to fight single enemies like the last boss of Dungeon of Forsaken, Vierna Da'Sheer.
Flute has also made a thorough guide of Dungeon of Forsaken. She has summarized all the boss and strategies that she usually uses to fight all the bosses in that guide. You can check it here. If you ever have a question, please don't hesitate to ask. :)