Cannot complete "Remove the Heart" Quest

Here's a solution that worked for me: I went back to Techiix and talked to Buxil (She's on the first building on the right when you first enter). She didn't have the talk icon next to her but you can still talk to her by pressing the talk button near her. I talked through all the conversation options. When I went back to the elevator, it was green instead of red and there were no more Kett infinitely spawning. 
Note: In my Journal entry, it said that I had destroyed 21/3 landing platforms.