Try this formula

=IFERROR(INDEX($A$2:$A$15,MATCH(TRUE,MMULT(--(ROW($A$2:$A$15)>=TRANSPOSE(ROW($A$2:$A$15))),$B$2:$B$15)>=ROWS($1:1),0)),"")


...confirmed by pressing CTRL+SHIFT+ENTER to activate the array, not just ENTER. You will know the array is active when you see curly braces { } appear around your formula. If you do not CTRL+SHIFT+ENTER you will get an error or a clearly incorrect answer. Press F2 on that cell and try again.