Nokia Lumia :: Unable To Disconnect Call & Noise While Receiving Calls

1. I can't disconnect calls. I generally happens when I'm on back to back calls. The phone becomes unresponsive for about 10~15 seconds before you could do anything with it.

2. When I'm listening to music and someone calls me, I hear a sharp noise when phone call overlaps music. Once I disconnect the call, the volume in the headsets remains fixed, you can't reduce or increase the volume. The solution here is to remove the headset from phone and plug them back in. If that doesn't work then re-start the phone!