I am meeting the requirements for challenges, but, not getting credit, when I go to clear it. I am currently working on the Artifacts challenges in Kaerok, and keep getting the HP% items at 4 stars, but, it won't allow me to clear it. What gives?

I am also stuck wioth using silver keys in the Tower. I cannot fight any battles that use silver keys.  If I fight a secret room, and lose, does it not use the key? I m not strong enough to defeat the room I am working on... Help?