HI, ABOUT 8 MONTHS AGO I FITTED A GROHE CONCEALED CISTERN PUSH FLUSH AS ABOVE. THE FLUSH WORKS BY AIR PRESURE. THE FLUSH HAS STOPPED WORKING. I HAVE CHECKED THE BUTTON AND IT IS STILL PUSHING AIR INTO THE AIR HOSE. I HAVE PUSHED AIR THROUGH THE HOSE MYSELF USING MY MOUTH AND THE FLUSH STILL DOES NOT WORK. THE OTHER END OF THE HOSE IS STILL ATTACHED AND HAS NOT COME LOOSE.ANYONE KNOW WHAT I SHOULD DO NEXT.