Not able to add call

[Former user]

Coolpad Note3 Lite [MT6735] Not able to add call... if I touch add call it mutes instead. Also if I get a second call my phone it just gives me the beep sound of second call and doesn't wake the screen. I have to wake it and see whose calling and if I answer it by swiping upward the call is received but the screen continues to show incoming call receive screen. Phone basically hangs into that incoming call receive screen. I have to do a soft reboot to come out of it.