broken volume up/on button

after some fiddling taking it apart, the problem seems to be that the volume down part of the button had a hard cap to be able to press the mechanical switch, and the on button didn't. I attempted to take a piece of ABS and a drop of acetone to melt it on top but it still seems not good enough to push the switch, not really sure where to go from here or if I could buy a new one of the buttons to just replace it.