I have a Galaxy S4 mini but when someone calls they cannot hear me but I can hear them. It does work when on Speaker phone and I guess this is due to the mic on the top of the phone is used for Speaker and the one at the base is used normally. I've checked and the mic hole hasn't any fluff in there and factory reset didn't work either. The phone was purchased off of ebay recently and i'll probably end up sending it back but wondered if there is a fix i hadn't heard about yet? Does anyone know if there is an app or a way that I can switch the primary mic from the base to use the working one at the top in all situations?