When I place a call

Question

When I place a call on my lg ke850 Prada cell phone the person who I call can hear me but I can not hear anything. The speaker phone works, you can hear every touch you make on the phone and I can also use a bluetooth with it but when placing a call i have that problem and it just happend all of a sudden. I bought the phone in May of this year and paid more than a $600 for it. Can somebody help. It's like new.