How do I keep jungle Vayne/Kayle down?
Just lost a game against a jungle Vayne despite FBing her at level 2 and then killing her in a countergank and stealing her camps. Its like if you don't live in her jungle, where laners can easily collapse on you, you can't keep her down. If even one of your lanes loses, now you have a dilemma: do you save that laner or do you keep counterjungling? If you keep counterjungling, the fed enemy laner will now come to kill you easily since you are in their (likely warded) jungle. If you don't counterjungle, Vayne can solo carry her team.
You can't late game against a jungle Vayne/Kayle the way you can against melee devourer junglers. The solution to jungle Yi is CC and burst. It is much harder to CC and burst a Vayne due to her range and mobility alone. Needless to say, Kayle is pretty much invulnerable to burst if played well.
I just don't know how to keep them down if even one lane loses.