Callers cannot hear me unless I turn on speaker phone! I have a Samsung Galaxy S2 (SGH-S959G) and it is a Straight Talk phone (don't know if that makes a difference or not). Anyway, I have only had this phone for about 6 or 7 months.

Around August 16, 2013 I noticed that when someone calls me or I call someone I can hear them but they cannot hear me unless I turn on speaker phone. I got in touch with Straight Talk and the representative instructed me to:


turn the phone off, 
take the battery out, 
take the SIM card out, 
clean the SIM card by wiping it on my shirt or whatnot, 
and then replace the SIM and battery. 


He then said to make a call, which I did and it worked. 

However, two days later it started back doing the same thing by repeated the instructions listed above in the exact same manner several times and it did not work. It still does not work. 

Also, when I call voicemail and change my personal settings, it will record what I say without it being on speaker. So I'm not quite sure why I am able to be heard in that manner but not when talking to someone.

Also, every now and then when I sit my phone down on a counter, the phone will just randomly turn off. 

There really is no good reason for that to happen unless I was throwing it down, which I am not. I have always taken good care of my things, especially my $350 phone. It's ridiculous to pay this much and only be able to use it for 6 or 7 months.

Please Help.
Try disabling "Noise Cancellation" on your device.