Just got a replacement device 2 days ago and when i went to make a call yesterday noticed i couldnt hear anything until i pressed the speaker button.
My original one worked fine. I dropped my phone and cracked the screen which is the reason for the replacement and was very frustrated when i noticed this. Just contacted assurion so hopefully they will do something
First I would recheck all sound and call settings also the earphone jack for audio and if normal, because this is a rebuilt I would consider a return. A two day old phone should not be having any issues unless perhaps the problem was already present but intermittent. Go back and let your warranty/insurance or Verizon handle this.
Assuming that your Bluetooth, if any, is not connected then you may have gotten another dud. Obviously your volume is turned up as the ear and speaker are controlled by the same level. I have heard of this issue coming from replacements where they only wipe the phone and re-flash the software, but don't really check anything else as long as it powers on and the radios work. I'd contact Verizon ASAP to look into another replacement. Believe me, I know...I'm on my 4th G2.
A call to Asurion would be in order.
I'm think what your doing is the correct step and good luck.