ChristinaB, I must let you know that lowering the volume was the VERY first thing done; I never have my volume high. Tech support told me over & over it was a network issue.
I'm still somewhat angry with VZW because after talking to tech support several times, I was assigned a tech agent (wish I could post his name on here but it will probably be removed) who lied about helping me. Even though I had also been to a couple of local stores about the echo, as of yesterday, I finally found a supervisor at another local store who went WAY ABOVE AND BEYOND to help me. She was absolutely awesome!!! She stated the tech agent documented my file advising the problem had been resolved yet he never called to inform me and I was still holding a defective phone. She stated not to worry, she will take over the situation & do all she can to fix it. She tested the phone, heard the echo & stated she did not think it was a network issue. The only resolution she could finally come up with was to replace the device again. Actually tech support said the same yet again, he never calledback to setup the exchange. Another issue (minor) came up with the new device later that evening, I went back, and she stayed with me for quite some time to make sure the device was working as should and that I was happy. This is my third DINC2 and I think it's finally working properly. I've been using it all day today and last night & I'm just excited. 
I do appreciate ChristinaB that you were doing a follow up since tech support and MarquiaF did not assist but it's fine now. Thank you for your time. (The supervisor I dealt with need to be cloned and put in every location of VZW. She was just that pleasant & professional).