Just a couple of things to add.

If you're not receiving incoming calls, simply go here and do the following:

https://www.google.com/voice?ui=desktop#phones

Click on "Google Chat".

This worked for me.

As for contacts on your tablet, make the images exactly 384 x 384 pixels in size if you don't want the pictures distorted.

Also, you might want to change the notification graphics on your tablet since they are a gaudy looking eyesore.