Get rid of Vayne's true damage
Replace it with magic damage. True damage should not even be in anyone's kit at all, it's unbalanced and there is no counteraction aside from HP which everyone knows an ADC can melt in a second cause of how much you have been favoring them Riot.
Quit being a piece of shit Balance Team.
And fix what is clearly broken.
ruins her day, just because your the ADC doesn't mean you aren't supposed to build SOME defense.