Help! Sometimes while on a call, I must cheek something on the call screen and it will either disconnect the call, or make the other person unable to hear me. It's not the mute button as I have tried to click it and nothing happens. It is also not lit up. I do try to hold the phone away from my face, and I rarely hold the phone between my face and shoulder (although if I do, it's more likely to happen). Any suggestions?