SE will not give you any refund. It is in the ToS.

Tired of hitting that Level-Lock? Then keep doing the highest dungeon you have unlocked so you can obtain the Current level Aetherial/Unique gear (Mages want full Battlemage set from 32-43).

Once you've maximized your items, you should probably be 2-3 levels ahead of your 'Level requirement' (up to current max level). Also, do your daily Low Level roulette and other roulettes.