I think it was a very bad idea of you to tie a particular armor to a certain dungeon. By only getting the badges you need from one single dungeon, you are forcing players into doing the same one over and over again.
This will burn them out, of course. And they are already complaining, of course.
They can’t say, hey lets try another dungeon, because they then get a whole other currency they can’t use for anything.
You should have at least 3 dungeons in explore mode tied to an armor set, then you’d have 2 armor sets to chose from and it would be a better gameplay decision. You are trying to do too much with too little.
You made some bad calls for the MMO genre, and they are all starting to show. Great game, but you made mistakes. Fortunately not big ones, most of them can be corrected via patches.