When the calls i want to end the calls the screen doesn't automatically gets on. Also some occations the with the incoming calls also the sreen doesn't gets switched on therefor unable to accept the calls
Sorry your having this issue.
Firstly you need to be sure theres nothing covering the sensor. Its located under the screen near the camera. If you have any screen protectors or cases this may effect this.
Secondily you can test the sensor in the test mode using *#77692*# and selcting sensor.
On this screen you can toggle the sensor on and off and also test by putting your hand on the screen, where ti should turn green and vibrate.
If this doesnt work. I would certaintly contact our support centre. on 0330 7267864.
Hope this helps