Y axis sliders

Has anyone seen these sort of sliders around on the internet? I've been looking and can't find any sliders that allow movement both ways like the stock ones do (just one way like a typical drawer slide). The reason I ask is because I believe my slides are bent. The middle of my build plate is the lowest part of the bed, when extended to either extreme the heights are the same. The bed is not warped.

 

Why don't you ask team robo to send a replacement? They're a weird kind of slider