Power and volume buttons sunk inside the body of Oneplus 3

So, the power and volume buttons on my OnePlus 3 started feeling a little weird lately and slowly one by one all just kind of sunk inside the body of the phone and stopped working altogether. So, I opened the phone and found that the actual internal buttons were fine and working, but the rubber thingy that pushes those buttons from outside and worn out and was unusable. So, does anyone know if those rubber thingys can be replaced or is there any diy hack to make them work or do I need to get the whole back cover replaced?