Have had this phone connected and working fine for over two years. However, now have a problem. When unknown numbers call, they are screened correctly and announced correctly. The number is displayed but I am then unable to get any of the button presses to cause a response e.g. Pressing 1 should accept the call once but nothing is happening. I have three handsets and they all have the same effect. All handsets and the base have been reset but the problem is the same. Have spoken to BT Product Help and they suggested changing all of the handset screensavers to 'Clock'. Have done this but the problem is still the same. Product people suspect a line fault but the line people have checked it and say there is no fault. Any suggestions?