Asking for help regarding X.H.Dun

Boston

my level 83,having Z.He,P.De,T.S.Chi and H.Zhong,both 80 lv and 81lv
My armament first 3 both level 33 and bottom 3 both 3 level and all with lv 6 and 5 gems,further i have polished first two armament.
my all 4 heroes foster are in 30-40% to full
all my equipments refinement are average level 3

i have been stucking in getting X.H.Dun for three days,craving for seeking kind advice from seniours in COTK

Thanks in advance dude

Boston

i have passed xh dun,thanks dude