I had the same problem with my R shoulder button too, I had to apply alot of pressure for the button to register. However now it has completely stop working. I took the whole controller apart and realised the cover for L and R are joined so their one plastic, however crappy designed and fragile it may be, in my case surprisingly it wasnt at fault, actual tactical button the thing that looks like a circle disk thing ontop on a cube was. To be honest, if you had the tools ie the torque screwdriver then it might be worth ordering the part from ebay and fixing it your self, otherwise the tools and replacement parts end up close to a working second hand controller on