Hi, I used the headset that came with my Nokia 3650 the other day and now my phone switches back and forth between headset mode and regular mode every few minutes or hours even when the headset is not plugged in. Is my phone broken or is there a way to fix this? Also, sometimes when I make phone calls the person on the other end can't hear me.

Dirt in the headset connector hole on the phone? Try to blow it out with a can of compressed air, or something.