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.
OK phone for texting & phone calls, even the Internet is usable on it providing you limit downloads. However, you can only add 4 or 5 small Apps or fewer games on it before it runs out of system memory. I could only get one card game App on mine. I had to delete 2 Apps from my phone because I couldn't download the newer version of my Jet Blue App even though all 3 Apps were on my SD card which was 95% empty.
The pre-installed Apps cannot be moved to the SD card and they take up 90% of the phones memory and then eventually more & more of the remaining 10% with their incessant updates. Even moving Apps you download onto the SD card have to be deleted to make room for any new Apps to be downloaded even though you have many GBs of SD memory available. Apparently some phone memory is still needed for updates to those Apps and the pre-installed Apps on the phone (which you can't delete).
Eventually I will have to delete another of my Apps to make room for the pre-installed updates (most of which I don't use nor want).
Lastly, you cannot block spam or nuisance calls on the phone unless you first add it as a contact and then block them individually. This doesn't work because the spam callers use new numbers every time they call. There are no settings to allow only contacts to call you or spam filters.