Help Callers can hear themselves (echo) on LG G3 (VS985)

[Dezso]

A couple of weeks ago I started to experience a problem on my Verizon LG G3 (Model VS985) where the other person can hear his or her own voice, so in other words, their voice echoes. I've tried turning the speakerphone on and off and calling people on both landlines and mobile, and many times they report being able to hear their own voice. I've even had people hang up on me because they get so irritated by the echo. I called Verizon, and they told me that it's a microphone issue, and that the only way to fix it is to replace the phone altogether. Since there is a small dent on the phone, they won't replace it under warranty, but only if I pay a $129 replacement fee. It puzzles me because it has been months since I've dropped the phone, and I haven't had any issues with it until a couple of weeks ago. So how does the microphone just break all of a sudden???