I just bought this phone a few months ago and its been working fine, I just upgraded on the prepaid to the $35 a month so I have calling, and it worked great for a couple weeks. But now It makes no noise. Except when you turn it on and off. The speaker won't turn on, when I press Speaker on it does nothing, Ringtones don't work, It just happened randomly today. I can make and receive calls but cannot hear nor' speak.
could be a hardware issue, have you tried a master reset? If that doesn't work, i would recommend calling LG if its under the 1yr manufacturer warranty or see about replacement options