I just got this phone last week. When I make a call, others have trouble hearing me. If I turn the speaker on it helps. One person heard me fine. Another said she could hear me but it was garbled. One should not have to use the speaker for others to hear me.
I've had the phone for a few months now and I don't like it at all. I'm not a big Cellphone user, I only have 2 Apps left installed, Amazon Alexa and the App for my security camera. Even with those 2 apps, I get constant warnings that I'm out of space for updates. The Apps can not be moved to the SD card, which is a huge design flaw. If you just want to talk on the phone and take pictures, the phone is fine. If you use any apps such as Alexa, security camera, endoscope, UVC reader, you will be constantly uninstalling apps and reinstalling them as you use them. It also can not be upgraded to Android Marshmallow, which does allow Apps to be moved to the SD card.