Its probably a gear level thing as a big part of it (a lot of people try doing this stuff in really substandard gear and wonder why they cant beat it). Now Im not a summoner main so take this next part with a grain of salt but have you been using EVERYTHING in your kit? Ive seen people complain in game about quests like these and when you ask them "Have you tried using your tank egi to peel for you" the response I get is "Tank egi is dumb! No one uses it!" Now Im not a summoner, but I know a minion that can voke mobs off you so you can have more space to do other things in the fight would kind of be useful? Im not saying do the entirety of the fight with tank egi either. Just when you need it, and pull another one out when you dont.

Point is you have a pretty expansive kit and if youre geared but still failing, it might be youre not using your kit to its fullest potential or your strategy for the fight isnt being thought out.